Receiving a French inheritance-tax bill after a death in the United Kingdom can be unsettling, particularly when the bill includes interest and a late-filing increase. The words used by the French tax office are technical: a déclaration de succession is the inheritance-tax return, droits de mutation à titre gratuit are tax charges on a gift or inheritance, and a majoration is a statutory increase added to the tax. A British executor or heir may also be waiting for a grant of probate, bank statements, valuations or a notarial document before knowing the estate’s full position.

That administrative difficulty does not, by itself, stop the French deadline. The practical question is therefore not simply whether the return was late. It is whether the correct deadline was used, whether the French tax actually applies to the assets and the people concerned, whether the calculation distinguishes tax from sanctions, and whether another professional caused or increased the loss. This article focuses on a UK heir or executor dealing with France after Brexit. It does not replace a review of the death, residence, will, assets, treaty position and correspondence. The aim is to show what should be checked immediately and how an evidence-based challenge can be organised.

I. What French inheritance-tax late-filing penalties mean for a UK heir

A. Which deadline and declaration apply after a death connected with the UK?

The starting point is the date of death, not the date on which a British heir receives a UK grant of probate, the date on which a French notary opens the file, or the date on which a bank releases information. Article 641 of the French Code général des impôts (General Tax Code) gives a six-month period where the deceased died in metropolitan France and a one-year period “dans tous les autres cas”, meaning all other cases. The official wording is set out in the current text of Article 641 CGI. A death in England, Wales, Scotland, Northern Ireland or another country will normally fall within the one-year limb. A death in France will normally raise the six-month question. The relevant facts still need to be checked where there are several deaths, a declaratory judgment, a missing person or an unusual date of legal death.

Nationality is not the test in Article 641. A British citizen who dies in France does not obtain a one-year period merely because the family, the will or the bank accounts are British. Conversely, a French national who dies in the UK is not put into the six-month category merely because the heirs are French. The location of the death is the first calendar question. The tax office will also need the date on which the return was actually registered, not only the date on which an adviser says that it was posted. Keep the acknowledgement, the registration stamp, the secure-message receipt and any proof of delivery.

The requirement to file and the question of tax liability are separate. Article 800 CGI requires heirs, legatees and donees to submit a detailed declaration, subject to limited thresholds and exceptions. The rule is visible in the official text of Article 800 CGI. For a direct-line heir, surviving spouse or civil partner, the €50,000 exception depends on the gross estate being below the threshold and on the absence of certain earlier gifts. For other persons, the threshold is much lower. A UK heir should not assume that a modest French bank balance or a foreign will removes the French filing duty. The gross estate, earlier gifts, insurance arrangements and the identity of each beneficiary must be reviewed together.

Article 750 ter CGI then addresses the territorial reach of French inheritance tax. It can bring worldwide movable and immovable assets within the French charge where the deceased had French tax residence. It can also apply to French assets when the deceased was not French tax resident, and to assets received by an heir who has had French tax residence for at least six of the ten years before receiving them. Those are different gateways, and a treaty or a foreign tax credit may change the final amount without removing the need to analyse the French return. The official Article 750 ter text should be read with the actual residence history rather than with a passport.

Brexit does not turn the UK probate process into a French tax filing. A grant of probate is authority for the personal representative to deal with the English, Welsh or Northern Irish estate; it is not a French déclaration de succession. In Scotland, confirmation has a different name and a different process, but the same practical warning applies. The French return may be due while a UK court application, an asset search or a dispute between beneficiaries is still unresolved. The UK government’s probate guidance treats valuation, reporting and probate as linked UK steps. French law adds a separate reporting and payment track.

The legal reason is the heir’s status in the succession. Article 724 of the Civil Code states that heirs designated by law are vested automatically in the deceased’s property, rights and actions. The phrase used by the text is “Les héritiers désignés par la loi sont saisis de plein droit des biens, droits et actions du défunt”. The official Article 724 Civil Code page is therefore relevant when an heir argues that a disagreement over entitlement postponed every tax obligation. It does not decide every tax dispute, but it explains why a beneficiary may have to act before the family has finished arguing about the estate.

A British heir should make four dates visible on one page:

1. the date and country of death;
2. the date on which the six-month or one-year period expired;
3. the date on which a complete or provisional French return was submitted and registered; and
4. the date of any French demand, mise en demeure (formal notice to file), assessment or payment.

Do not replace those dates with the date of the will, the date the notary was instructed, the date of the probate grant or the date of the first call with the tax office. Those events may explain why information was missing, but they do not automatically reset Article 641. If a late return is being defended, the defence should identify a legal reason for a different deadline or a documented reason why the surcharge was not lawfully triggered.

Earlier gifts are another frequent source of an incorrect return. Article 784 CGI requires earlier gratuitous transfers to be reported in the succession declaration so that the applicable fiscal history can be reconstructed. The official Article 784 CGI text refers to donations made previously, whatever their form. A British family may have a deed of gift, a trust distribution, a deed of variation or a transfer recorded in UK terminology rather than in French terms. The document should be translated for the French file and classified carefully; describing it as a “family payment” does not answer whether it was a gift, a loan, a trust interest or an estate distribution.

There is also a difference between the person who must coordinate the filing and the person who ultimately bears the economic cost. A notary may prepare and submit the forms, an executor may supply information, and several heirs may be jointly involved in the tax liability. Those roles should be stated in writing. A file that says only “the notary handled everything” leaves uncertainty about instructions, authority, delivery and the professional advice given. A file that says only “the UK executor was responsible” may ignore a French professional’s knowledge of the deadline and the possibility of an early provisional declaration.

B. How are French interest and late-filing increases calculated?

A French bill may contain at least three different components: the inheritance tax itself, interest for late payment or late regularisation, and a late-filing increase. They do not have the same legal basis and they should not be challenged with the same argument. A mistake in the tax base is not identical to a late return. A cash-flow problem is not identical to an absence of notice. A request to cancel a sanction is not the same as a request to recalculate the inheritance tax.

Article 1727 CGI supplies the interest rule. The current text states that a tax claim not paid within the legal period gives rise to late-payment interest, and says: “Le taux de l’intérêt de retard est de 0,20 % par mois”. The official Article 1727 CGI text also explains the starting point and end point of the calculation. In the ordinary mechanism, interest is calculated from the first day of the month following the month in which payment was due until the last day of the month of payment, subject to the detailed rules in the article.

Article 1728 CGI addresses a late declaration. Its general structure provides a 10% increase where there has been no formal notice or where the declaration is filed within the period allowed after a formal notice, and a 40% increase where the declaration is not filed within that period. For succession declarations, paragraph 2 contains a specific timing rule: the 10% increase begins on the first day of the seventh month following expiry of the six-month period in Article 641, and the 40% increase applies when the declaration has not been filed within ninety days after receipt of a formal notice. The official Article 1728 CGI text is the source to use because the general wording and the succession-specific paragraph must be read together.

Item on the French statement	Legal question	Evidence to request
Inheritance tax	Were the assets, debts, relationship and territorial rules correctly identified?	Declaration, valuations, liabilities, residence history and treaty analysis
Interest under Article 1727	What was the legal due date and which months were counted?	Tax calculation, registration date, payment dates and accounting ledger
10% increase	Was the succession-specific start date applied correctly?	Article 641 deadline and date of the registered declaration
40% increase	Was there a valid formal notice and was the ninety-day period respected?	Notice, proof of receipt, filing acknowledgement and correspondence

For example, if a person died in the UK, the one-year Article 641 deadline is the first date to calculate. If the return was filed after that period but before the succession-specific 10% trigger, the tax office should not simply apply an increase from the day after the first anniversary. If a formal notice was later served, the date it was received and the date the return was registered become decisive for the 40% question. The example does not determine an individual bill: bank holidays, incomplete returns, corrections, additional declarations and the version of the law applicable to the death must be checked.

Article 1701 CGI explains why a dispute about the amount does not normally authorise an heir to wait indefinitely before filing or paying. The article says that inheritance-transfer duties are paid before registration and that no one may defer payment “under the pretext of a dispute over the amount”, while preserving a possible claim for restitution. The official Article 1701 CGI text should be considered before deciding to retain the whole amount. A carefully documented payment made with an express reservation is often safer than silence, although the correct strategy depends on the amount, liquidity and advice received.

Article 1717 CGI creates a possible exception for payment arrangements: the payment of certain registration duties and land-registration taxes may be split or deferred under regulatory conditions. The official Article 1717 CGI section is deliberately short; the practical eligibility conditions are found in the associated provisions and regulations. An heir should therefore ask for a written decision on whether the particular inheritance tax qualifies, what security is required, and how interest is treated. A payment facility is not a declaration deadline extension, a cancellation of principal tax or an automatic cancellation of late-filing increases.

The 2026 wording of Article 1728 also makes it important to separate late filing from deliberate inaccuracy. A valuation dispute, a missing foreign account statement or a disagreement over the scope of a will may concern the tax base and evidence rather than the date of filing. The administration must identify the legal basis of each amount. If the statement combines Article 1727 interest, an Article 1728 increase and a reassessment, ask for the calculation in separate lines. That simple request often reveals whether the tax office has used the wrong date, the wrong percentage or the wrong principal.

A UK executor should also compare the French calculation with the UK estate file without assuming that one replaces the other. HM Revenue & Customs may require full details of UK Inheritance Tax assets and debts before probate, while France may require a declaration based on French residence, French assets or the heir’s residence history. The GOV.UK guidance on valuing an estate describes the UK reporting and probate sequence. It does not calculate French inheritance tax, but it can help identify the death certificate, will, asset schedule and debt evidence that should be collected for both administrations.

Finally, check whether a France–UK tax convention or domestic credit rule changes the amount ultimately payable. The 1963 UK legislation implementing the France–UK Death Duties Convention is an official starting point for the treaty text. Its application depends on the deceased’s domicile, the location and nature of the assets, and the tax charged by each country. Even where a credit or allocation rule reduces double taxation, it does not automatically change the Article 641 filing deadline. Treaty analysis and late-filing analysis should appear as two separate conclusions in the written advice.

II. How can a British heir challenge or reduce a French late-filing surcharge?

A. Which challenge, remission or notary claim should be filed first?

The first response should preserve the estate’s position, not wait for a perfect file. That normally means identifying the French tax service dealing with the succession, obtaining the registered declaration and calculation, and asking the notary or executor to explain every missed date. If no declaration has been filed, the question of a provisional declaration should be raised immediately. If a declaration has been filed, a corrective return may be needed. The best route will differ where the dispute concerns the very existence of a French filing duty, the amount of the tax, the percentage of the sanction, or the conduct of a professional.

There are four distinct arguments to test:

1. The deadline argument. The death was outside metropolitan France, the date used by the tax office is wrong, or the filing was registered earlier than the statement suggests.
2. The obligation argument. An Article 800 exception, the gross-estate threshold or another legal fact means that the return or a particular part of it was not required in the form asserted.
3. The calculation and procedure argument. The tax base, territorial link, prior gifts, interest months, formal notice, percentage or ninety-day period has been misapplied.
4. The responsibility argument. A notary or another adviser knew that the estate was incomplete, failed to warn about the danger of delay, or failed to propose a provisional return and partial payment when that was the practical way to reduce the loss.

These arguments can coexist. An heir may file a return while expressly reserving the right to challenge the sanction, pay an undisputed amount and request a calculation of the balance. A provisional filing does not necessarily mean that the heir accepts the final asset values, the final distribution or every tax consequence. The written covering letter should state what is known, what remains under investigation, which documents are missing and when a corrected declaration will follow. Avoid vague wording such as “the estate is blocked”; identify the precise document, person, jurisdiction or account that caused the delay.

Where the administration proposes a fiscal sanction, Article L80 D of the French Tax Procedure Code requires the decision to be reasoned and gives the taxpayer a period of thirty days to make observations before the sanction is imposed. The official section containing Article L80 D should be read with the notice actually received. Check the date of notification, the address or electronic account used, the legal text cited, the amount of tax used as the base, the percentage applied and the period allowed for response. A response should be sent in a way that proves delivery and should attach a chronological index of the evidence.

A remission request is different from a legal challenge. Article L247 of the Tax Procedure Code allows the administration, in defined circumstances, to grant full or partial remission of fiscal fines or tax increases and to transact over non-final penalties. It also refers to interest under Article 1727. The official Article L247 text does not create a general right to cancel inheritance-tax principal. A remission request should therefore state whether it seeks a reduction of interest, a 10% or 40% increase, or another sanction; it should not present an inability to pay as if it proved that the tax was legally wrong.

In practice, a remission request is stronger when it explains the cause, the taxpayer’s conduct and the steps taken to regularise. Attach proof of the death date, the date instructions were given, the date information was requested from UK institutions, the date documents arrived, the date the notary or adviser warned about the deadline, and the date payment or filing was attempted. Evidence of serious financial difficulty may support a request about sanctions or payment, but financial difficulty alone does not prove that the filing was on time.

If the estate could not pay all duties, ask separately about a lawful split or deferred payment under Article 1717 and its implementing rules. A request should include a realistic schedule, available cash, expected asset sales or distributions, proposed security and the identity of the person who will make each payment. It should not simply say that UK assets are inaccessible. Explain why they are inaccessible, which institution holds them, what court or probate step is pending, and what interim payment can be made.

A claim against a notary is also separate from a tax claim. The tax office decides whether the French assessment and sanction are due; a civil court may later decide whether a professional’s fault caused a recoverable loss. The two files should not be allowed to undermine each other. Preserve the engagement letter, powers of attorney, emails, telephone notes, draft declarations, requests for documents, fee invoices, reminders, warnings and proof of what the heir understood at each stage. A professional-liability claim needs causation: the evidence must show not only a failure to warn but also what an informed heir would have done and which part of the surcharge would probably have been avoided.

The document pack for a British heir should normally include the original or certified death certificate, the will and codicils, the UK grant of probate or confirmation where relevant, the family relationship documents, a full asset and debt schedule at the date of death, bank and investment statements, details of UK and French residence, earlier gifts, insurance policies, trust documents, the French notary’s mandate, all tax notices and all filing receipts. Ask a French professional which documents need an apostille and sworn translation; do not assume that an ordinary English translation will satisfy the receiving institution. The firm’s contact form can be used to send the essential dates and document list for an initial review without replacing the late-filing analysis.

The first seven working days can be organised as follows:

1. Ask for the complete tax calculation, the registered declaration, the formal notice and proof of receipt.
2. Create a date table from death to payment, with a source next to each date.
3. Separate French tax, Article 1727 interest, Article 1728 increase and any other reassessment.
4. Check Article 641, Article 800 and Article 750 ter against the actual death and residence facts.
5. Send a written request for missing documents to the notary, banks, HMRC or the probate court.
6. Respond to any Article L80 D observations period before it expires.
7. Decide, in writing, whether the immediate step is a return, corrective return, payment, payment-facility request, remission request, tax claim or professional-liability review.

Do not confuse that list with a requirement to finish the estate in seven days. Its purpose is to stop an unexamined assumption from becoming a final tax position. It also makes it easier for counsel to give a useful opinion: the adviser can see which dates are proved, which are disputed and which missing document would change the result.

There is a separate practical distinction between a tax office request and a notary’s request. A notary may ask for a power of attorney, a certified identity document, a UK probate document or a valuation to complete the succession file. The tax office may need a declaration and payment even if the notary has not completed every civil-law step. Copy the relevant exchange to both sides and ask each recipient to state whether it is refusing to proceed, unable to proceed, or merely waiting for one named document. That wording can later matter when causation and diligence are assessed.

B. What does French case law say about disputes, notary delay and evidence?

The leading warning for a cross-border family dispute is Cour de cassation, Commercial Chamber, 18 October 2011, no. 10-25.074. The deceased had died abroad and the heirs argued that litigation about the distribution of the estate prevented timely filing. The Court of Cassation held that the heir, automatically vested in the succession, had to file within the statutory period and could not rely on a dispute about the devolution of the succession to escape that duty. The judgment uses the words “l’héritier, saisi de plein droit de la succession, a l’obligation de procéder à la déclaration dans les délais légaux”. It also rejected the attempt to use the administrative-position guarantee applicable to a reassessment as a way to erase sanctions attached to the original late return.

The factual analogy is important for a British heir waiting for a grant of probate, a will dispute or a court decision in the UK. The case does not say that every exceptional obstacle is irrelevant. It says that a dispute over who receives the estate is not, on its own, a substitute for the tax declaration. A defensible file should therefore show why the obstacle made a timely filing legally or practically impossible, what provisional information was available, what was offered to the tax office and why an earlier declaration could not have been made.

Professional advice is tested separately. In Cour de cassation, First Civil Chamber, 6 March 1984, no. 83-11.445, a notary had not filed within six months because the estate’s composition was not yet precise. The Court upheld the finding that the notary should have explained “la nécessité de souscrire une déclaration, fût-elle provisoire” and the “risques de pénalités fiscales”. A provisional return and an advance payment could have reduced the consequences without necessarily amounting to an acceptance of the succession. The decision is not a rule that a notary must guarantee a zero surcharge; it is a rule about information, options and the causal loss caused by failing to present them.

The same line appears in Cour de cassation, First Civil Chamber, 18 June 1996, no. 94-10.753. The Court held that the presence of a personal adviser did not reduce the notary’s duty to advise and referred to “les dangers d’une déclaration tardive de la succession”. The notary had not specifically drawn attention to those dangers or proposed provisional declarations and partial payments. For a UK family, a financial adviser, accountant or probate solicitor may have been involved, but their presence does not automatically answer what the French notary knew, what the notary was instructed to do and what advice was actually given.

In Cour de cassation, First Civil Chamber, 26 November 2002, no. 99-17.745, the Court again treated the notary’s personal warning as significant. The judgment criticised the absence of proof that “le notaire eût personnellement averti son client des sanctions encourues” before the six-month deadline expired. The case involved an estate without sufficient immediately available funds. It does not make lack of cash a universal defence. It does show why the correspondence should distinguish a refusal to pay from an inability to pay, a request for a payment arrangement, a request for a provisional filing and an unexplained period of inactivity.

A fifth decision is useful where the tax loss is connected with a later correction rather than the initial declaration. In Cour de cassation, First Civil Chamber, 20 December 2012, no. 11-27.959, the Court required the lower court to examine whether the notary knew of information allowing a corrective succession declaration to be filed within the period required by the administration. The case should not be stretched into a rule about a property purchase, which is outside this desk. Its narrower lesson is that the professional’s knowledge, the moment when it was acquired and the available corrective step must be reconstructed from documents, not inferred from the fact that a penalty later appeared.

Those decisions also show why the legal claim must be framed carefully. A tax challenge may seek cancellation or reduction because the administration applied the wrong deadline, wrong base or wrong procedure. A remission request may ask the administration to moderate a sanction despite a technically late filing. A claim against a notary may seek damages equal to the loss caused by a missed warning or missed provisional step. The remedies, defendants, time limits and proof are different. A letter that mixes all three without identifying the relief sought is harder to process and easier to reject.

Evidence is not limited to the final declaration. Article 1353 of the Civil Code places the burden on the person claiming performance of an obligation and on the person claiming discharge to prove payment or the event that extinguished it. The official Article 1353 text says “Celui qui réclame l’exécution d’une obligation doit la prouver”. In this context, that principle supports a disciplined evidence table: who says the date was extended, where is the written extension, who says the declaration was sent, where is the registration receipt, who says the estate could not be valued, what request proves that limitation, and who says the notary warned about a provisional filing, where is the warning?

A UK executor should preserve electronic evidence in its original format where possible. Export secure messages, retain the original email headers, save delivery confirmations, record the time zone used for telephone calls and keep both the English document and the sworn French translation. A bank statement that arrives in pounds may need a date-of-death exchange-rate explanation. A UK will may require a French legal analysis rather than a literal translation. A grant of probate may prove authority but not the tax residence of the deceased or the heir. Each document should be assigned one proposition that it proves.

The French tax office may also distinguish an initially incomplete declaration from a complete declaration filed late, a corrective declaration caused by a newly discovered asset, and a reassessment caused by a disagreement over valuation. Those distinctions affect the applicable text and the causal explanation. If the file includes an overseas account, pension, trust, life policy or prior gift, list it even if the immediate argument is only about a surcharge. Omitting a difficult asset can create a second dispute and weaken the credibility of a request for leniency.

Finally, use the case law in the right direction. The 2011 decision warns that foreign litigation is not an automatic suspension. The 1984, 1996 and 2002 decisions show that a notary may be liable where the professional did not explain the deadline, the risks, a provisional return or partial payment. They do not guarantee success without proof of instructions, causation and quantifiable loss. A strong opinion will state which proposition each decision supports and will distinguish the facts of a UK estate from the facts of the reported case.

Conclusion

A French inheritance-tax surcharge received by a British heir after Brexit should be audited in a fixed order: death location and date, Article 641 deadline, Article 800 filing obligation, Article 750 ter territorial link, Article 1727 interest, Article 1728 percentage and formal notice, then the evidence of professional advice and payment capacity. Waiting for UK probate or for a family dispute to end is not automatically a defence. The cross-border documents may explain the delay, but they must be tied to a legal argument and a specific remedy.

File or correct what can be filed, preserve the right to challenge what is disputed, answer any thirty-day observations period, and keep remission, payment arrangements, tax claims and professional-liability claims distinct. A British executor should obtain the complete calculation and the registration proof before accepting the figures. A focused review can identify whether the surcharge is wrong, reducible or recoverable from a professional, while avoiding the more dangerous assumption that a UK probate document completes the French tax process.

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