Moving to France does not end the tax history of a house or flat that you keep in the United Kingdom. If you sell that property after becoming resident in France, you may have to calculate and report a UK capital gain within 60 days of completion, while also disclosing the transaction in France under the France–UK double taxation convention. The treaty can prevent the same gain from being taxed twice, but it does not turn the two filing systems into one return. The residence analysis, the location and use of the property, the date of completion, the reliefs claimed and the evidence kept for both tax authorities all matter.

The first distinction is between the State that has the primary taxing right and the State that still requires information for its own tax calculation. A UK property is immovable property situated in the United Kingdom. Article 14 of the current convention therefore gives the United Kingdom a central taxing right over the gain. France may nevertheless require a French-resident seller to report the foreign gain and apply the treaty relief method. A UK Private Residence Relief claim, an allowable loss, a joint ownership arrangement or an incorrect exchange-rate conversion can change the amount that ultimately remains due.

This guide is for an individual British reader dealing with the sale or intended sale of a directly owned UK property after Brexit. It covers the person’s residence, tax returns, proof and remedies. It does not explain how to purchase a property, create a company, transfer a home into a French société civile immobilière (SCI, a French civil property company), or structure a trust. Those facts can change the result and require a separate review before any deadline is missed.

I. What happens when a UK property is sold after you move to France?

A. Is the UK sale taxed in Britain, France or both?

Start with the treaty, not with the country in which the sale proceeds arrive. The relevant instrument is the 2008 France–UK double taxation convention published on Légifrance. It expressly includes UK Capital Gains Tax and French taxes on gains within its scope. Article 14(1), headed “Gains en capital”, provides: « Les gains provenant de l’aliénation de biens immobiliers définis à l’article 6 et situés dans un Etat contractant sont imposables dans cet Etat. » In English, a gain from selling immovable property is taxable in the State where that property is situated. For a house, flat or plot in England, Wales, Scotland or Northern Ireland, that points first to the United Kingdom.

This is why a French tax resident does not automatically file the transaction as if it were a French-property disposal under the domestic French property-gain regime. Article 150 U of the Code général des impôts (CGI, the French General Tax Code) concerns capital gains made on the paid disposal of built or unbuilt immovable property or related rights in the situations governed by French law. It is not a shortcut for applying every French property-sale calculation to a UK-situs property. The treaty must be read first, then the French return and relief mechanics must be matched to the gain’s legal category.

The treaty’s allocation does not necessarily mean that France can ignore the gain. Article 24(3) explains how France eliminates double taxation. It states that, for France, « les revenus qui sont imposables ou ne sont imposables qu’au Royaume-Uni » are taken into account for calculating French tax, subject to the convention’s credit rules. For gains falling under Article 14(1), Article 24(3)(a)(ii) refers to a credit for the UK tax paid, capped at the amount of French tax corresponding to those gains. The practical effect depends on the taxpayer’s treaty residence, the exact gain, the UK tax actually borne and the French calculation for the relevant year. A treaty credit is not a general refund of every pound withheld in Britain, and a French disclosure is not proof that France has a second full charge.

The domestic French starting point is equally important. Article 4 A CGI says: « Les personnes qui ont en France leur domicile fiscal sont passibles de l’impôt sur le revenu en raison de l’ensemble de leurs revenus. » That worldwide-income rule is then limited or adjusted by a treaty. Article 4 B CGI identifies the household or main stay, professional activity and centre of economic interests as domestic indicators, while also recognising that an international convention can treat a person as resident elsewhere. A British owner who has moved the family, work and ordinary life to France should therefore assume that residence is a legal question to document, not a conclusion supplied by a British bank address.

Article 170 CGI imposes a detailed income declaration on a person taxable to French income tax. Its opening words are: « toute personne imposable audit impôt est tenue de souscrire et de faire parvenir à l’administration une déclaration détaillée de ses revenus et bénéfices ». The French tax authority’s current Form 2047 page says that the form is required where a person domiciled in France has received income outside metropolitan France and the overseas departments. The official guidance on foreign-source income also lists foreign capital gains and explains that the treaty determines the reporting line and the credit or effective-rate method. The correct form combination can change, so use the current form and notice for the year of the sale.

The convention’s wording has been tested in litigation. In Cour administrative d’appel de Paris, 22 September 2023, no. 21PA04416, the court applied the current France–UK convention to gains connected with shares and held that the disputed gains were taxable only in the United Kingdom under the relevant treaty wording. The decision records the phrase « les gains en litige ne sont taxables, en tout état de cause, qu’au Royaume-Uni ». That case was not a direct sale of a UK house, but it shows why the asset category and the precise paragraph of Article 14 matter. A seller should not replace the property rule with the rule for shares, partnership interests or other assets.

A second useful warning comes from Conseil d’État, 27 July 2012, no. 337656. The case concerned the former France–UK convention and the UK remittance basis. The Conseil d’État held that a person subject to UK tax by reason of residence did not lose UK treaty residence merely because foreign income could be taxed later on remittance. The decision describes the position as « n’est pas susceptible de perdre la qualité de résident fiscal du Royaume-Uni ». The current convention and post-Brexit domestic rules must still be checked for the year concerned, but the principle is practical: the tax treatment of a payment and the treaty residence status of the person are related questions, not identical ones.

Article 14 also contains traps for owners who do not hold the property directly. Paragraph 2 covers shares or rights deriving most of their value from immovable property in a Contracting State, and rights in a partnership or trust whose assets are mainly such property. Paragraph 5 sends other gains to the State of residence, subject to paragraph 6, which preserves a State’s right to tax certain gains of a person who was resident there during any of the six preceding tax years. A direct sale of a UK home, a sale of shares in a property company and a sale of a trust interest therefore cannot be placed into the same box. If a company, partnership or trust is involved, pause before filing a personal property return.

The headline answer for a directly owned UK property is therefore: calculate the UK gain and comply with the UK deadline; establish whether you were French tax resident at the relevant time; disclose the foreign transaction in the French return where required; and claim the convention’s relief in the manner prescribed for that gain. A French return may show the gain for rate or credit purposes without creating a second unrestricted French capital-gains bill. Conversely, a UK exemption does not by itself prove that no French information or calculation is needed. Keep the two analyses together but do not merge them.

B. Which residence date, property use and ownership facts change the answer?

The date to place at the centre of the file is completion, not the date on which you first advertised the property or exchanged contracts. HM Revenue & Customs (HMRC) asks for both the exchange date and the date on which ownership ended, but the 60-day payment and reporting clock for a residential UK property runs from completion. Compare that date with your move to France, your French tax-residence facts, the date your French home became available and any period during which you remained UK resident under UK rules. A sale agreed in December but completed in January can fall into a different tax year and a different filing timetable.

Do not treat a long-stay visa, a residence permit, a French address or a UK passport as a complete answer. Immigration status gives permission to live in a country; tax residence allocates taxing rights under domestic law and the treaty. The Service-Public guidance on leaving France or living abroad is useful background, but the tax convention remains decisive where both States claim residence. Prepare a calendar showing physical presence, the availability of each home, the location of the household, employment and business activity, and the place from which financial decisions were made.

If both countries treat you as resident under their domestic law, apply the treaty residence article. It examines factors such as a permanent home, the centre of vital interests, habitual abode and, if necessary, nationality and an agreement between the competent authorities. The conclusion can be different from the answer produced by a simple count of days. A person can become French treaty resident before selling a UK property while remaining within a UK domestic tax year that runs from 6 April to 5 April. Record the facts rather than forcing the sale into a single “move date”.

The property’s history changes the UK calculation. If it was your only or main home for the whole period, you may qualify for all or most of HMRC’s Private Residence Relief. The official guidance lists conditions including occupation as the main home, limits on letting, limits on exclusive business use, the size of the grounds and the intention when buying. Relief can be apportioned where the home was occupied for only part of the ownership period. Moving to France does not automatically remove relief for the years in which the UK property was genuinely your main residence, but the post-move period must be examined.

A former home that was let, used as a holiday property or retained as an investment requires a period-by-period schedule. Keep tenancy agreements, letting-agent statements, council-tax records, utility bills, insurance documents, travel evidence and correspondence showing when the property was available to you. A room let while you lived there, a whole-house letting after departure and an empty property awaiting sale are not necessarily treated in the same way. Do not describe every vacant period as residence or every period of occupation as qualifying relief without checking the statutory conditions and the current HMRC guidance.

Joint ownership adds a second reporting file. HMRC’s official property-return guidance says that each joint owner reports their own gain or loss. The percentage in the title, any declaration of trust, transfers between spouses or civil partners, the date each person acquired their interest and any different relief entitlement should be preserved. The French household return may bring spouses or civil partners together for French income-tax purposes, but that does not eliminate the need to compute each UK owner’s share. A sale statement addressed to one owner is not enough evidence for the other owner.

Inherited property, a gift, a property acquired before marriage, and a home transferred between connected persons each require a separate acquisition-value analysis. The estate file, probate valuation, gift documents and any connected-party valuation may be more important than the eventual completion statement. If the property belonged to an estate, a personal representative may have different obligations from the beneficiary. If a partnership or trust owns the asset, Article 14(2), the entity’s tax status and the beneficiary’s residence must be reviewed before a personal filing is submitted.

Currency can create a hidden difference between the UK and French calculations. The UK computation is normally prepared in pounds sterling. French reporting instructions require foreign amounts to be converted into euros using the applicable official method. The current Form 2047 notice states that foreign-currency receipts are converted into euros and explains how foreign-source amounts are reported. A seller should keep the exchange-rate source, the date used, the sterling calculation and the euro translation as separate lines. Do not convert the final UK tax bill to euros and call that figure the French gain: the two countries may apply different dates and tax bases.

Article 14(6) deserves a specific mention for a person who left the United Kingdom before selling another asset. It preserves a six-year look-back rule for certain gains under the treaty. For a directly owned UK property, the situs rule in Article 14(1) is usually the first rule because the property remains in the United Kingdom. For shares, fund interests or another asset, the six-year provision can alter the result. This is one reason an article about a UK property sale must not be reused without amendment for a UK share portfolio or a transfer into an SCI.

Finally, distinguish the tax on the gain from annual ownership charges. Council tax, business rates, UK rental income, French taxe foncière, inheritance tax, mortgage redemption and estate administration may appear in the same sale file, but they do not all reduce the capital gain. The purchase process is also outside this article. Your working paper should identify each payment by its legal purpose before deciding whether it belongs in the UK gain computation, the French declaration or neither.

II. How do you file, correct and challenge the two tax positions?

A. What must be filed in the UK within 60 days and reported in France?

For a residential property in the United Kingdom completed on or after 27 October 2021, HMRC’s current reporting guidance states that a taxable capital gain must be reported and paid within 60 days. The dedicated UK property reporting page repeats that deadline and warns that interest and a penalty may arise if the report and payment are late. If you are not UK resident, HMRC says that all sales of UK property or land must be reported by the deadline even when there is no tax to pay or the disposal produces a loss. That non-resident rule is wider than the question whether a final liability is positive.

Build the UK return in this order:

1. Confirm whether the asset is residential, non-residential or mixed-use and confirm the completion date.
2. Gather the acquisition price, acquisition date, buying costs, selling costs and the cost of qualifying improvements.
3. Calculate the gain or loss in sterling and test Private Residence Relief, losses, the Annual Exempt Amount and any other relief that is actually available for the tax year.
4. Open or use the HMRC Capital Gains Tax on UK property account, enter the property and ownership details, submit the calculation and pay the amount shown by the deadline.
5. Keep the submission confirmation, payment reference, calculations and supporting documents; if you are registered for Self Assessment, include the disposal there as HMRC requires.

HMRC’s checklist includes the property address and postcode, acquisition date, exchange date, completion date, acquisition and disposal values, costs of buying, selling or improving the property, reliefs and the property type where the seller is not UK resident. The information is not administrative decoration. It allows HMRC to test the legal calculation, the date of disposal and the reason why an amount is exempt. A bank statement showing the net proceeds will not prove the acquisition cost or the improvement expenditure.

Private Residence Relief must be calculated rather than assumed. The HMRC relief tool confirms that the question is whether and when the property was your only or main residence. The current guidance also explains that the last nine months of ownership can qualify in relevant cases, with special rules for certain disabled people and care-home residents. A former home that was let can produce a split gain. Retain the dates of occupation, periods of absence, letting evidence and proof of any relief claim. If relief reduces the gain to zero, a non-UK resident seller should still check the reporting rule rather than silently omitting the disposal.

For an illustration only, suppose a property was bought for £250,000, acquisition and qualifying improvement costs totalled £35,000, the sale price was £420,000 and selling costs were £10,000. The preliminary gain would be £125,000 before reliefs, losses and the applicable annual rules. That number is not the final UK tax and is not a French euro amount. If the owner lived in the property for part of the ownership period, the relief schedule may remove a proportion. If the owner is a non-resident, the complete disposal still needs to be reported under the HMRC rule. Keep the example structure in the file, but replace every figure with evidence from the actual transaction.

The French stage is separate. A French tax resident should review the current 2047 notice and the 2042 return for the year in which the gain arose. The official impots.gouv.fr answer on a foreign property gain says that a person domiciled in France must in principle declare a foreign property gain, while a treaty can exempt the gain from French tax and affect whether a 2048 property-gain form is required. That page also warns that the relevant declaration depends on whether the gain is taxable in France. For a UK property, do not copy the filing route for a French notaire-supervised sale: read the France–UK treaty and the current year’s notice together.

In practical terms, the French file should show the gross gain, the legal character of the asset, the completion date, the sterling computation, the euro conversion method, the UK tax due and paid, the treaty article relied upon and the French line or annex used. If the gain is exempt in France but retained for an effective-rate calculation, the amount may influence the rate applied to French-source income without becoming a second ordinary charge on the same gain. If the treaty method gives a credit for UK tax, record the credit calculation and its cap. A missing UK payment certificate can prevent the credit being accepted even where the treaty principle is correct.

Article 30 of the convention sets an evidence standard for treaty benefits. It requires a declaration identifying the income or gains, an attestation from the other State’s tax authority confirming treaty residence for the relevant period, and any other supporting document requested by the competent authority. The source text refers to « toute autre pièce justificative que l’autorité compétente du premier Etat contractant peut exiger ». In practice, assemble the treaty file before submitting the French return, not after a query. An HMRC calculation, a UK tax payment record and a French residence certificate are often more useful together than separately.

The minimum evidence bundle should contain:

• the signed completion statement and contract, with the completion date clearly identified;
• the purchase contract, acquisition statement, title evidence and any probate or gift valuation;
• invoices for acquisition, disposal and qualifying improvement costs, with proof of payment;
• mortgage statements showing redemption separately from costs that may enter the gain calculation;
• occupation, absence and letting records supporting or limiting Private Residence Relief;
• the ownership percentages, declaration of trust and any transfer between spouses or civil partners;
• the HMRC property-account submission, payment reference, tax computation and any Self Assessment entry;
• the French 2047 and 2042 copies, the treaty calculation, the exchange-rate evidence and the UK tax certificate;
• residence, nationality and household documents for the tax year; and
• all letters, online messages and deadlines issued by HMRC or the French tax service.

Keep a one-page chronology at the front of the file. It should show acquisition, occupation, letting, departure from the UK, arrival in France, exchange, completion, HMRC submission, payment, French filing and any assessment. This chronology is particularly valuable when the sale crosses 5 April, when one spouse moved before the other, or when a UK completion took place shortly before a French annual return. It also helps identify whether a document relates to the tax year of the sale or to an earlier period of ownership.

Do not claim a treaty credit simply because tax was deducted in the United Kingdom. Article 24 limits the credit to the treaty category and the French tax corresponding to the relevant income or gain. UK withholding, an estimated payment or a payment later refunded by HMRC is not necessarily UK tax “effectively borne” for the final French calculation. Wait for the UK position to be sufficiently documented, or explain the provisional position and correct the French return if HMRC later changes the amount.

B. What if the return is late, the credit is missing or the bill is wrong?

If the UK 60-day deadline was missed, act on the HMRC side first and preserve evidence of the reason for the delay. Use the UK property account to view or change a previous return where the online route is available. If the account cannot be used, HMRC’s official postal reporting guidance explains when a form must be printed and sent. A late payment or report can produce interest and a penalty, but a late filing is not a reason to wait for the French return. Submit the accurate UK calculation, pay what is properly due or request the appropriate correction, and keep the submission timestamp.

On the French side, a missing foreign gain should be regularised as soon as the error is identified. Depending on the stage of the file, that can mean using the online correction service, sending a signed explanatory letter with an amended schedule, or addressing the tax office that manages the return. State clearly whether the omission concerns the amount, the treaty classification, the exchange rate, the UK tax credit or the failure to report the gain at all. Attach the calculation and the documents that allow the officer to reproduce it. A vague request to “cancel the tax” is weaker than a precise request for correction, credit or discharge supported by the treaty paragraph.

French law distinguishes interest from penalties. Article 1727 CGI provides: « qui n’a pas été acquittée dans le délai légal donne lieu au versement d’un intérêt de retard. » The same article sets the ordinary interest rate at 0.20% per month and contains rules for certain spontaneous corrective filings. The calculation must be made by reference to the tax actually due and the applicable procedural facts; do not add a blanket percentage to the UK tax and present it as French interest.

Late French declarations can trigger the rules in Article 1728 CGI. The current text starts with « Le défaut de production dans les délais prescrits d’une déclaration » and provides different rates according to whether there was a formal notice and what happened afterwards. An incorrect or incomplete declaration can instead raise Article 1729 CGI, which provides a 40% increase for deliberate failure and 80% increases for the more serious situations described by the text. Those rates are not automatic conclusions from a foreign-property error. The taxpayer’s conduct, the notice history, the explanation and the evidence of good faith must be analysed.

If France has already assessed tax by omitting the treaty credit or by treating the UK home as a French-situs property, use the formal claims procedure. Article L190 of the Livre des procédures fiscales (LPF, the French Tax Procedure Code) places claims seeking the correction of an error in the basis or calculation of tax within the contentious claims jurisdiction. Its wording refers to « la réparation d’erreurs commises dans l’assiette ou le calcul des impositions ». The claim should identify the assessment, the amount challenged, the treaty article, the calculation requested and every supporting document.

If the tax authority sends a proposed adjustment, answer the proposal within its stated period and address each reason. Article L57 LPF requires a proposal to be reasoned so that the taxpayer can make observations or accept it. The provision says that the proposal must be « motivée de manière à lui permettre de formuler ses observations ». A response should therefore challenge the residence analysis, the asset classification, the UK tax amount, the exchange rate and the treaty relief separately where those points are wrong. Attach a comparison schedule rather than sending only a narrative denial.

Observe the domestic claim deadline. Article R*196-1 LPF currently states that, for most taxes other than local direct taxes, claims must be filed by 31 December of the second year following the relevant event, such as collection or payment of the tax. It also contains specific starting points and exceptions. The safe working rule is to calculate the deadline from the assessment or payment immediately, record it in the chronology and file before the last day. A request for informal help does not necessarily preserve a formal claim.

A treaty dispute can also justify a mutual agreement procedure, known in French as a procédure amiable. Article 26(1) of the convention allows a resident who considers that one or both States have imposed, or will impose, tax contrary to the convention to submit the case to the competent authority. The official text states that « Le cas doit être soumis dans les trois ans » after the first notification of the measure causing the non-conforming taxation, or within the alternative six-year period specified by the article. This route is independent of domestic remedies, but it is not a reason to abandon the UK correction, the French claim or an objection to collection. File every domestic deadline while the competent authorities examine the treaty issue.

The competent authorities may ask for proof of treaty residence and of the tax actually borne. That is why Article 30, the UK tax calculation, the French assessment, payment evidence and the residence file should be indexed. If HMRC refunds the UK tax after France has granted a credit, update the French position. If France refuses a credit because HMRC tax was only estimated or later reimbursed, obtain the final UK statement and ask for the French calculation to be corrected. A treaty relief file is a living record, not a single form submitted once.

Case law confirms the importance of proving the underlying residence facts. In Cour administrative d’appel de Versailles, 15 December 2015, no. 14VE01586, the court considered evidence of a UK residence and the application of the former France–UK convention; it found that the available material did not establish the necessary UK tax subjection. In another UK treaty dispute, Cour administrative d’appel de Paris, 17 February 2012, no. 10PA01988, the court relied on tax returns, account records and an official document to establish the UK residence condition. The factual contexts differ, but the message for a property seller is direct: produce official evidence, not an assertion based on nationality or an address.

Use this escalation sequence when the two returns do not match:

1. freeze the completion statement, UK and French returns, assessments and payment evidence in one indexed file;
2. recalculate the UK gain in sterling, including reliefs, losses, ownership shares and qualifying costs;
3. recalculate the French euro amount using the current official instructions and classify the treaty method;
4. correct HMRC’s property return and any Self Assessment entry, keeping the date and reference;
5. send the French correction or formal claim, citing Articles 14 and 24 of the convention and the relevant CGI and LPF provisions;
6. challenge any proposed adjustment under Article L57 LPF and any final assessment within the Article R*196-1 period; and
7. consider the Article 26 mutual agreement procedure if both States continue to tax the same gain contrary to the convention.

The most common practical errors are predictable. Sellers confuse exchange with completion, assume that moving abroad cancels Private Residence Relief, omit a disposal because the UK tax is zero, claim a French credit for an unfinalised UK payment, use the French property-sale form without analysing the treaty, and let a correction letter sit unanswered because the amount is still being discussed with HMRC. Each mistake can be prevented by a dated chronology and two reconciled calculations. The fact that the sale proceeds are paid into a French account does not decide where the gain is taxable; the location of the property and the treaty classification do.

If the transaction is still planned, begin before exchange. Ask the conveyancer for a projected completion date, ask HMRC or a tax adviser which account and calculation will be needed, assemble the occupation and improvement evidence, and tell the French tax adviser that a UK property gain will arise. If completion has already happened, count 60 days immediately and work in parallel on the UK report and the French treaty file. If a notice or assessment has arrived, identify the response and claim deadlines before opening a general discussion with either authority. A cross-border correction succeeds more often when the first letter contains the legal classification, the numbers and the evidence.

This article is a general legal information guide, not a calculation of an individual’s liability. The result can change with the tax year, the property’s use, the ownership structure, treaty residence, nationality, the final UK tax and subsequent legislative amendments. Where a sale involves an estate, a company, a partnership, a trust, a connected-party transfer or competing residence claims, obtain advice on the complete file rather than filing a copied return.

Conclusion

A British owner who sells a UK property after moving to France should treat the transaction as a coordinated two-country process. The United Kingdom normally has the primary right over a gain from UK immovable property, and the residential-property reporting clock can expire 60 days after completion. France may still require the gain to be disclosed and included in the treaty calculation if the seller is French tax resident. The relief mechanism depends on Article 24, the actual UK tax and the current French forms; it is not created by simply attaching a UK payment receipt.

Keep the completion date, property history, ownership shares, relief evidence, sterling calculation, euro conversion and residence proof together. If an omission or double charge appears, correct HMRC, file the French claim within the domestic deadline and preserve the option of the treaty’s mutual agreement procedure. The most valuable action is early: count the 60 days, classify the gain and build the evidence before the two administrations ask different questions.

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