A British couple can sign an English prenuptial agreement and still discover that a French notary, bank, creditor or court needs a separate answer to a more fundamental question: which law governs the couple’s matrimonial property? A “prenup” is usually understood in England and Wales as an agreement about financial consequences if the marriage ends. A French régime matrimonial, meaning the legal system governing ownership, management and liability between spouses, is wider. It can affect savings, business interests, guarantees, the family home and the assets that pass into a deceased spouse’s estate. Brexit did not create a single rule under which an English document is automatically accepted or automatically rejected in France. The outcome depends on the date of the marriage, the exact wording and form of the agreement, the couple’s first habitual residence, any express choice of law, the location of assets and the rights of third parties. This guide addresses the person and the couple’s cross-border legal life. It does not explain the French property purchase process, which belongs to a different desk. The practical answer is therefore cautious but useful: an English prenup can be powerful evidence and may be respected, but it should be reviewed and, where necessary, adapted through a French notaire (a French civil-law notary) before or soon after the move.

I. Will an English prenup govern a British couple’s assets after moving to France?

A. Which law applies when the couple has no French marriage contract?

The first mistake is to treat the document’s language as the answer. An agreement written in English and signed before a registrar in England may contain several different promises: a choice of law, a choice of matrimonial regime, a division of assets on divorce, a waiver of claims, or a schedule recording what each person owned before the wedding. Those functions are not identical. A French authority will ask what the couple actually chose, whether the choice was permitted, whether the form is valid, and whether the document can be relied upon against the person now asking for payment or transfer.

French law starts from contractual freedom, but only within legal limits. Article 1387 of the Code civil (French Civil Code) says that “La loi ne régit l’association conjugale, quant aux biens, qu’à défaut de conventions spéciales”. In English, the law governs the spouses’ property relationship only where they have not made special arrangements. That principle does not mean that every private document becomes a French marriage contract. It means that the agreement must be classified and tested against the applicable conflict-of-laws rules and mandatory protections.

Where the couple wishes to make a French matrimonial agreement, the formal requirement is particularly clear. Article 1394 of the French Civil Code provides that “Toutes les conventions matrimoniales seront rédigées par acte devant notaire, en la présence et avec le consentement simultanés de toutes les personnes qui y sont parties”. The English meaning is that matrimonial conventions are drawn up by a notarial deed with the simultaneous presence and consent of the parties. An English prenup is not automatically the same thing as that French deed. Its wording, execution, legal advice, witnesses, disclosure and intended legal effect all matter.

For an international marriage, the law governing the matrimonial regime may be chosen under the Hague Convention of 14 March 1978 on the Law Applicable to Matrimonial Property Regimes, where the Convention’s temporal and personal conditions are met. Article 3 permits a pre-marriage choice among specified connecting laws: the law of a State of which either spouse is a national, the law of a State where either spouse is habitually resident when the choice is made, or the law of the first State where one spouse establishes a new habitual residence after marriage. A British couple therefore needs to read the clause carefully. “This agreement is governed by the law of England and Wales” may be a governing-law clause for the contract, not a sufficiently clear choice of the law applicable to the matrimonial regime.

The Convention also separates formal validity from substantive effect. It states that a marriage contract can be valid as to form if it complies with the law applicable to the matrimonial property regime or with the law of the place where it was made, and that it must be in writing, dated and signed by both spouses. That is helpful for an English document, but it is not a guarantee of result. The French notary or court may still need to determine whether the document is a matrimonial property agreement, a divorce-only agreement, or evidence of the parties’ intention. A document that only says that each spouse will keep “pre-marital assets” may not answer what happens to earnings, investment growth, a French bank account, a guarantee or a house used as the family home.

If there is no effective choice of law, the couple’s first matrimonial connection becomes central. For marriages falling within the relevant period of the Hague Convention, the default rule generally looks to the State where both spouses established their first habitual residence after marriage. “Habitual residence” means the stable centre of the couple’s married life, not simply the address on a single form. A couple who married in London, spent their first married years living together in Surrey and moved to France later will need to distinguish the law applicable at the outset from the consequences of the later move. A couple who married in England but immediately established their joint life in France presents a different analysis.

The French case law shows why a file based only on nationality or the place of the ceremony is unsafe. In Cour de cassation, First Civil Chamber, 5 November 1996, no. 94-21.603, the published summary states that the applicable law for spouses married without a contract is determined mainly by the first matrimonial domicile. The decision also records that a stable establishment in France could evidence an intention to submit the couple’s financial interests to French law, independently of other indicators such as common nationality or the place of the wedding. This is a precise reason to preserve tenancy agreements, employment records, tax registrations and correspondence showing where the married life actually began.

That first-home indicator is not an irrebuttable rule. In Cour de cassation, First Civil Chamber, 22 November 2005, no. 03-12.224, the Court described the first matrimonial domicile as a simple presumption that can be displaced by relevant evidence, including the spouses’ consistent financial organisation and a document referring to their chosen regime. The source uses the phrase “ne constitue qu’une présomption simple”, meaning that the first home is a starting point, not the end of the inquiry. An English prenup, if clear and authentic, may therefore be central evidence; it does not remove the need to prove what the parties chose and how the choice was expressed.

For marriages after 1 September 1992, French courts have treated the Hague Convention as applicable in appropriate cases. In Cour de cassation, First Civil Chamber, 13 April 2016, no. 15-17.541, the Court examined a marriage after that date and the absence of an express choice of applicable law. The decision is a warning against using a later notarial document as a substitute for a genuine choice of law: a document adopting separation of property may not itself select the law governing the entire matrimonial regime. The legal question must be stated with precision.

There is a second question about time. The Convention’s rules do not simply ask what the couple owns today. They ask what law governed the relationship when the relevant choice, marriage, residence or transaction occurred. That is why a review should begin with a dated chronology: date and place of marriage; any earlier marriage contract; first joint home; moves between the UK and France; any later choice of law; acquisition dates; business or pension arrangements; and any loan or guarantee signed by one spouse. A later French address alone cannot rewrite the past, but it can trigger a new issue about a change of applicable law or the effect of the existing regime.

B. Does Brexit change the Hague Convention, the first matrimonial home or later evidence?

Brexit changes the institutional route through which a case may be handled, but it does not turn the expression “English prenup” into a conclusion. France remains a party to the Hague Convention, whose Article 2 says that the Convention can apply even where the nationality, habitual residence or designated law is not that of a contracting State. The Convention’s official text therefore matters in a France–UK file. A French authority will not decide the case merely by asking whether the United Kingdom is in the European Union today.

There can also be a difference between the rules used by a French authority and those used by a participating EU Member State. Regulation (EU) 2016/1103 is available on EUR-Lex. It concerns jurisdiction, applicable law and recognition in matters of matrimonial property regimes for the Member States participating in enhanced cooperation. It is not a universal replacement for the Hague Convention in every France–UK situation. The Regulation itself also excludes succession to the estate of a deceased spouse, maintenance obligations and social security from its scope. A British couple should not assume that one reference to the European Regulation answers the separate questions of divorce, matrimonial assets and inheritance.

The move to France may still have consequences where the couple made no choice and concluded no marriage contract. Under Article 7 of the Hague Convention, the law originally applicable can continue despite a change of nationality or habitual residence. The same provision contains limited mechanisms by which the law of the spouses’ common habitual residence can become applicable in defined circumstances, including a long period of residence. Article 8 then deals with the temporal effect of such a change and protects third-party rights. The practical lesson is simple: do not tell a couple that a move to France automatically changes its regime, and do not tell it that a move can never matter.

Evidence becomes even more important when the couple has lived in several countries. The marriage certificate may show no contract, while a separate English agreement exists. The agreement may contain an English choice-of-law clause but no description of the matrimonial regime. A French bank may ask for a French translation and proof that the document is still operative. A creditor may say that the arrangement was not publicised. A divorce court may ask whether the agreement was freely made and fair in its practical effect. Each question uses a different legal lens.

French decisions illustrate the conflict-of-laws method. The 1996 and 2005 cases cited above show the role of the first matrimonial home and the possibility of rebutting a presumption. The more recent Cour de cassation, First Civil Chamber, 1 July 2026, no. 24-15.575, concerned the Hague Convention and common foreign nationality where one spouse also held French nationality. The Court held, in the official summary, that “La circonstance qu’un époux a une double nationalité française et étrangère ne fait pas obstacle” to identifying a common foreign nationality in the circumstances covered by the Convention. The case is not a British prenup case, but it shows that connecting factors must be applied rather than replaced by a shortcut based on one passport.

The UK side has its own distinction. In England and Wales, a prenuptial agreement has traditionally not been automatically enforceable as if it were a statute. The official Supreme Court record for Radmacher (formerly Granatino) v Granatino, [2010] UKSC 42 identifies the leading decision. The Government’s current explanation states that the Supreme Court expected a couple to be held to a nuptial agreement where it was freely entered into, with a full appreciation of the circumstances, unless it would be unfair to do so. That is a strong framework for an English court, but it is not the same as saying that a French court must treat the document as a French contrat de mariage (marriage contract).

For that reason, a British couple should separate four questions in its advice letter. First, which law governs the matrimonial property regime? Secondly, does the prenup validly express a choice or define a regime under that law? Thirdly, how will a court deal with the agreement if the marriage ends, including financial needs and fairness? Fourthly, can the arrangement be relied upon against a bank, purchaser, landlord, tax authority, creditor or French estate administration? A “yes” to one question does not supply a “yes” to the other three.

There is also a boundary with inheritance planning. The matrimonial regime determines what belongs to each spouse and what remains after a first death. The succession law then determines who inherits and whether a will, forced-heirship rule or cross-border instrument changes the result. The Hague Convention expressly excludes succession rights of a surviving spouse, and Regulation 2016/1103 excludes succession to the deceased spouse’s estate. A prenup should therefore be read alongside, not instead of, a will and a succession review. A separate guide on whether a UK will works in France after Brexit is relevant to that second stage.

II. What should a British couple do before France exposes the gap?

A. How do French rules affect the family home, savings, debts and inheritance?

If French law governs and there is no effective contrary arrangement, the couple may fall under the French statutory community regime. Its full name is communauté réduite aux acquêts, meaning community limited to property acquired during the marriage, subject to the detailed Civil Code rules. Article 1400 provides that “La communauté, qui s’établit à défaut de contrat”. Article 1401 then explains that the community includes acquisitions made by either spouse during the marriage and savings from the fruits and income of separate property. In practical English, the default is not simply “everything is joint” or “everything follows the name on the account”. The date, source and documentary trail matter.

Article 1401 uses the French word acquêts for the assets generated or acquired during the marriage. The relevant text states: “La communauté se compose activement des acquêts faits par les époux ensemble ou séparément durant le mariage”. An investment portfolio held by one spouse can therefore require analysis beyond the name printed on the statement. The source of contributions, reinvested income, transfers between accounts and changes in value may have to be reconstructed. A prenup with an asset schedule is useful because it gives the notary or court a starting record, but later conduct can still create questions.

Proof is not a technical afterthought. Article 1402 provides a presumption that a movable or immovable asset is a community acquisition unless it is proved to be separate under the law. The official text says: “Tout bien, meuble ou immeuble, est réputé acquêt de communauté”. The evidence may include completion statements, bank records, inheritance documents, company registers, investment ledgers, loan files and contemporaneous correspondence. A British couple who brings an English schedule of pre-marital assets should keep the original, a complete translation and the records showing that later money did not become mixed beyond reconstruction.

A different French regime is séparation de biens, meaning separation of property. Article 1536 states that when spouses have chosen it, each keeps administration, enjoyment and disposal of personal property and remains responsible for debts incurred personally, subject to the rules protecting household life. The article’s opening sentence is: “Lorsque les époux ont stipulé dans leur contrat de mariage qu’ils seraient séparés de biens”. This regime can offer a clearer framework for a couple with businesses, unequal contributions or pre-existing obligations, but it is not a promise that every asset registered in one name will remain insulated from every claim.

Ownership still has to be proved. Article 1538 provides that, between spouses and against third parties, a spouse may prove exclusive ownership by any means. It begins: “Tant à l’égard de son conjoint que des tiers, un époux peut prouver par tous les moyens qu’il a la propriété exclusive d’un bien”. If neither spouse can establish an exclusive right, the statutory presumptions and co-ownership consequences become important. The lesson for UK accounts, shares and household contents is to maintain an evidence file, not merely a paragraph in a prenup.

The family home is governed by a mandatory protection that a contract cannot be treated as casually removing. Article 215 of the Civil Code states that spouses cannot, without each other, dispose of the rights securing the family home or the furniture with which it is furnished. The official wording begins: “Les époux ne peuvent l’un sans l’autre disposer des droits par lesquels est assuré le logement de la famille”. This is not a guide to buying a French property. It is a warning about the daily legal life of a couple: a sole title, a separate-property clause or an English promise may not allow one spouse to ignore the other spouse’s statutory protection of the family home.

Household debts operate under another mandatory rule. Article 220 provides that each spouse can enter alone into contracts for household maintenance or the education of children, and that the resulting debt can bind the other spouse jointly. Its text begins: “Chacun des époux a pouvoir pour passer seul les contrats qui ont pour objet l’entretien du ménage ou l’éducation des enfants”. The provision contains exceptions, including manifestly excessive expenditure and certain instalment purchases or loans. A prenup cannot be used as a blanket answer to a French supplier or landlord asking who is liable for an ordinary household obligation.

Guarantees and loans need a separate check. Article 1415 says that one spouse cannot engage more than personal property and income through a guarantee or loan unless the other spouse gives express consent, and that the consenting spouse does not thereby engage personal property in the same way. The relevant opening is: “Chacun des époux ne peut engager que ses biens propres et ses revenus”. The English prenup should not be drafted as if a private allocation of risk automatically changes the rights of a French lender or creditor. The transaction documents and the law governing the third-party relationship must also be reviewed.

These home and debt rules belong to the French régime primaire impératif, meaning the mandatory core rules that apply to married couples whatever their chosen matrimonial regime. Article 226 makes the point in broad terms: “Les dispositions du présent chapitre … sont applicables, par le seul effet du mariage”, subject to the provisions that reserve the application of matrimonial conventions. In English, the couple cannot assume that choosing English law or separation of property removes every rule that French law treats as fundamental to married life.

Death exposes the difference between the matrimonial regime and succession most sharply. Suppose a spouse dies owning UK investments, a French account and an interest in the family home. The first task is to identify what belongs to the survivor, what belongs to the matrimonial community or co-ownership, and what forms part of the deceased spouse’s estate. Only then can the notary or other estate professional apply the succession law, a will, a choice-of-law provision or a tax treaty. If the prenup says “the survivor receives everything”, that wording may be ineffective or incomplete: it could be a matrimonial allocation, a testamentary promise, a waiver or simply a statement that conflicts with mandatory law.

The same distinction matters on divorce. The French court may have to liquidate the regime, meaning calculate and divide the spouses’ property relationship, before assessing other financial claims. An English court may approach a prenup under the Radmacher principles, but a French court dealing with a French-law regime will first need to know whether the document chose English law, chose a French regime, or only recorded an intended outcome. The couple should not confuse an agreement that limits a divorce award with a document that determines whether an asset was jointly owned from the day it was acquired.

A short example shows the risk. James and Eleanor marry in London in 2021 and sign an English prenup saying that each keeps assets owned before marriage and that English law governs. They live together in Kent for three years, then move to France. Eleanor continues to receive UK employment income into her own account; James funds renovations and signs a loan alone. If a dispute arises, the file must answer whether the English clause is an express choice for the matrimonial regime, whether it meets the applicable form, whether the agreement covers post-marriage income and debts, what the French family-home rules require, and whether the lender knew or could rely upon the regime. The names on the accounts do not answer all five questions.

Now change the facts. They married in 1990, never lived together in England after the ceremony, began their married life in France, and signed a later English document in 2005 without a clear choice-of-law clause. The temporal scope of the Hague Convention, the law applicable before and after its entry into force for France, the parties’ presumed intention and the evidence of their first matrimonial home all need to be assessed. The answer cannot be copied from a couple married in 2021. Date-sensitive conflict rules are not a footnote; they may decide which legal system classifies every major asset.

B. Which documents and notarial steps make the arrangement usable in France?

The safest approach is a coordinated review before the move or as soon as the couple decides that France will be its stable home. The objective is not to translate a document mechanically. It is to produce a coherent file that a French notary, court, bank or creditor can read without having to guess what the couple intended. The file should also state what remains uncertain. A carefully limited conclusion is more useful than a certificate that promises automatic recognition.

1. Identify the legal system behind the words “English prenup”. Confirm whether the agreement is governed by the law of England and Wales, Scots law or another law. Check whether it was prepared as a prenuptial agreement, a postnuptial agreement, a separation agreement or a wider asset declaration. Do not treat “UK law” as precise enough for a French reader.
2. Collect the executed original and every schedule. Preserve the signed agreement, asset schedules, amendments, side letters, financial disclosure, lawyer correspondence and any document showing that each person received advice. A draft with tracked changes is not the same as the executed instrument. If the original is held by a solicitor, obtain a certified copy and record how it was certified.
3. Build a marriage and residence chronology. Add the date and place of the wedding, the first joint home, later addresses, dates of arrival in France, tax-residence changes, nationality changes and any previous relationship or civil partnership relevant to the document. Include proof such as tenancy agreements, council-tax records, employment contracts and official registrations. The aim is to make the first matrimonial residence and later moves demonstrable.
4. Separate choice of law from choice of regime. Ask the drafting lawyer or notary to identify the exact clause that chooses the applicable law. Then ask what regime that law produces: separation, community, deferred sharing or another arrangement. A sentence about who pays the mortgage is not necessarily a choice of matrimonial law. A sentence about divorce is not necessarily a choice of ownership rules.
5. Prepare a controlled French translation. A French traduction certifiée is a certified translation used for official purposes. The notary can say whether one is required and who may prepare it. Do not let several informal translations circulate with different meanings for “property”, “estate”, “maintenance”, “trust”, “beneficial interest” or “separate”. The translator should work from the final signed version and retain the document structure.
6. Check authentication requirements document by document. An apostille is a certificate authenticating the origin of a public document for use abroad; it does not prove that every statement in the document is legally correct. The French notary or receiving authority should confirm whether an apostille, certification, legalisation or no additional authentication is required for the particular UK document. This avoids both an unnecessary delay and the more serious error of assuming that an apostille validates the prenup’s substance.
7. Ask a French notaire to classify the agreement. The notary should be asked in writing whether the document is capable of being recognised as a matrimonial property agreement, whether an express choice under the applicable international rules is present, and what French mandatory provisions remain applicable. The request should refer to the couple’s exact dates and first residence. A generic statement that the couple is “protected in France” does not answer the legal questions.
8. Map third parties and publicity. “Publicity” here means the formal information or registration that allows third parties to know which regime applies. The Hague Convention recognises that a State may restrict reliance on a matrimonial regime against a third party unless publicity or knowledge requirements are met. Ask how the arrangement will be mentioned in civil-status records, notarial instruments and dealings with lenders. A private agreement kept in a drawer may be effective between spouses yet difficult to invoke against someone who had no reasonable way to know about it.
9. Reconcile the asset schedule with current evidence. For UK pensions, investment accounts, shares, trusts, business interests, inheritances and gifts, identify the owner, source, date and current account. For French assets, retain deeds, bank statements and loan documents. Do not assume that a pension, trust or company interest is classified in the same way under English and French law. If the couple’s records are incomplete, state the gap and obtain evidence before a death, divorce or creditor dispute creates a deadline.
10. Review the family home and all guarantees. Record who occupies the home, whose rights secure it, who signed the mortgage or other loan, and whether either spouse has guaranteed another person’s debt. Article 215 and Article 1415 may matter independently of the chosen regime. The review should also cover ordinary household contracts under Article 220, because a separation clause does not necessarily defeat the statutory rules for household life.
11. Coordinate the prenup with wills and beneficiary forms. Each spouse should have advice on the succession law that may apply, the treatment of children from an earlier relationship, UK pension nominations, life insurance and French estate administration. The prenup should not contain a casual inheritance promise that conflicts with a later will or a mandatory heirship rule. Changes to a will or beneficiary form should be signed through the correct channel and kept with the matrimonial file.
12. Decide whether a French amendment is needed. If the English document is unclear, incomplete or difficult to use against third parties, the couple may need a French marriage contract or a formal change of regime. Article 1397 permits spouses, in the family’s interest, to modify or change their matrimonial regime by notarial deed; the official text begins “Les époux peuvent convenir, dans l’intérêt de la famille, de modifier leur régime matrimonial”. The notary will explain the required liquidation, notices, opposition rights and effective date for the couple’s facts. Do not backdate a document or describe it as a simple translation if it changes the legal arrangement.

The timing of a French amendment matters. Article 1397 is not a formality that can be completed by one spouse alone or by sending an email to a UK solicitor. It is an act before a French notary, with the safeguards attached to a change of matrimonial regime. Adult children and creditors may have rights in the procedure, and the arrangement may have different effects between the spouses and against third parties. The notary must therefore receive a complete statement of debts, gifts, guarantees, businesses and earlier agreements before proposing a route.

The couple should also ask how the arrangement will be described in a later deed. A French instrument can be useful precisely because it gives a future notary a clear reference point, but it cannot erase a creditor’s pre-existing rights or turn a divorce-only promise into a universal ownership rule. A declaration should distinguish the law chosen, the regime chosen, the date from which it operates, the assets included, the assets excluded and the provisions that remain mandatory in France.

For a couple living in Paris or elsewhere in Île-de-France, the legal analysis does not become a special Parisian matrimonial regime. The practical advantage of obtaining advice locally may be access to a notary and counsel who can coordinate French records, a tribunal judiciaire (the ordinary civil court of first instance) and the relevant estate or family file. The governing international rules remain national, international or European rules, not a local Paris rule. The same chronology and document standards apply whether the home is in Paris, Lyon, Normandy or the Dordogne.

If a dispute has already begun, the response should be evidence-led. Preserve the original prenup and do not annotate it. Gather the marriage certificate, the certified translation, the residence chronology and the asset schedule. Ask the bank, notary or creditor to state in writing exactly why it refuses to rely on the document. If a French court is seized, raise the choice-of-law and regime issues early; waiting until the distribution of assets can make reconstruction harder. If a UK divorce or estate process is running at the same time, coordinate the timetable so that one settlement does not accidentally contradict the law governing assets in France.

The core question for the French reader will often be “Can I rely on this English prenup?” The practical answer is “possibly, after classification and verification”. The strongest file combines a clear clause, proper execution, independent advice, full disclosure, a dated residence history, a French legal analysis, a certified translation where required, publicity against third parties and aligned wills. The weakest file has a scanned draft, no asset schedule, no evidence of advice, no explanation of the first matrimonial home and a promise that Brexit makes English law automatically prevail. Those two files may contain the same number of pages, but they do not carry the same legal weight.

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Conclusion

An English prenup can protect a British couple moving to France, but “protect” does not mean “automatically enforce”. The agreement must be tested against the law governing the matrimonial property regime, the date and first habitual residence of the marriage, the Hague Convention where relevant, French mandatory rules and the rights of third parties. Brexit makes the cross-border route more important; it does not remove the need for that legal analysis.

Before relying on the document, obtain the executed version, prove the couple’s chronology, separate the choice of law from the choice of regime, translate the final text carefully and ask a French notaire to assess recognition and publicity. Review the family home, household debts, guarantees, UK investments and succession documents together. If the arrangement is incomplete, Article 1397 may provide a route to a formal change, subject to the notarial procedure and the protection of children and creditors.

The aim is a file that can be understood and used when the couple is healthy, solvent and cooperating. That is the moment to clarify the regime. Waiting until divorce, death or a creditor’s demand turns an avoidable drafting question into a dispute about proof, timing and third-party rights.