You have settled in France since Brexit, you pay your French income tax every spring, and now you are selling the house you kept in Manchester, Bristol or Bromley. Two tax offices immediately take an interest in the same sale: HM Revenue and Customs in London, because the bricks stand on English soil, and the Direction Générale des Finances Publiques in Paris, because you live in France. Each one has a legal basis for taxing you, and each one runs its own calendar, its own rates and its own reliefs. The good news is that the France–United Kingdom double tax convention of 19 June 2008 was written precisely for this collision, and it gives France — your country of residence — the job of eliminating the double taxation through a tax credit. The bad news is that the credit is capped, the French social levies have their own logic after Brexit, and the deadlines on the two sides of the Channel do not wait for each other. This article explains which country taxes what when a British person resident in France sells a home in the United Kingdom, how the French bill is calculated year by year, how to declare the sale in both countries, and how to challenge a bill that taxes the same gain twice.
I. You live in France and sell in England: which country taxes the gain?
A. France taxes your worldwide gains, and the United Kingdom taxes its own bricks: how do HMRC and the French tax office share your sale?
The starting point is your French tax residence. Under article 4 A of the French General Tax Code (Code général des impôts), “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. Celles dont le domicile fiscal est situé hors de France sont passibles de cet impôt en raison de leurs seuls revenus de source française.” In plain English: once France is your tax home, you are taxable on all of your income and gains, including the gain on a house in England. And article 4 B of the same Code defines that tax home broadly: “Sont considérées comme ayant leur domicile fiscal en France au sens de l’article 4 A : a. Les personnes qui ont en France leur foyer ou le lieu de leur séjour principal ; b. Celles qui exercent en France une activité professionnelle, salariée ou non, à moins qu’elles ne justifient que cette activité y est exercée à titre accessoire”. If your family home (your foyer), your main place of stay or your main professional activity is in France, you are a French tax resident, and the sale of your English house falls inside the French tax net from the outset.
On the other side, the United Kingdom taxes the same sale because the property is situated there. The double tax convention signed in London on 19 June 2008 — the treaty that still governs Franco-British tax relations after Brexit — says so expressly. Under Article 14 on capital gains, gains from the sale of immovable property may be taxed in the State where that property stands. Your flat in Leeds is immovable property situated in the United Kingdom, so the United Kingdom is entitled to tax the gain. In practice HMRC applies its own machinery: anyone who sells a UK residential property must tell HMRC about the sale within 60 days of transferring ownership, even where no tax is ultimately due, and a person who is not resident in the United Kingdom for tax purposes pays only on the part of the gain that arose since 5 April 2015, with private residence relief — including relief for the final 9 months of ownership where the conditions are met — reducing the taxable slice (guidance on tax if you live abroad and sell your UK home).
So both States may tax, and the treaty organises the sharing. Because the gain comes from immovable property in the United Kingdom, the United Kingdom taxes first as the State where the property sits, and France, as your State of residence, must eliminate the resulting double taxation. The mechanism is a tax credit granted by France. Under Article 24 of the Convention on the elimination of double taxation, the French credit for gains covered by Article 14 equals the tax paid in the United Kingdom, but it can never exceed the French tax attributable to the same gain. Two consequences follow. First, you must actually have paid definitively-assessed British tax on the gain before France credits anything: an HMRC estimate, a payment on account or a provision in your conveyancer’s file is not enough. Second, the credit can never exceed the French tax on the same gain. If the British tax is higher than the French tax — which happens regularly where the French holding-period relief has shrunk the French base — the excess British tax is simply lost. That cap is the single most expensive trap in the whole operation, and it is why the order of operations matters: compute the French base first, pay and finalise the British tax, then claim the capped credit on the French return.
One further treaty subtlety deserves attention before you exchange contracts. Paragraph 5 of Article 14 reserves to your State of residence the exclusive right to tax gains on any property other than the listed categories, but a later paragraph preserves each State’s right to tax gains realised by a person who is its resident in the year of sale or was its resident at any time during the previous six fiscal years. This six-year tail means a recent move does not wipe the slate clean: if you left France for Britain less than six years ago, France may still assert a taxing right over the gain under its domestic law. The mirror situation — leaving France and then selling the former French home — is examined in detail in our companion guide on selling a French home after moving back to Britain, exemption windows and the six-year treaty tail, and the two articles should be read together whenever a move and a sale happen within a few years of each other.
B. The six-year tail, the non-resident levy and the treaty shield: what recent court decisions teach sellers?
French courts have spent the last decade drawing the exact boundary between domestic tax law and treaty promises on property gains, and three recent decisions frame your position as a French-resident seller. The first concerns the levy that applies in the mirror case — a non-resident selling a building in France — and it is worth understanding because your conveyancer or your British buyer may confuse the two regimes. Article 244 bis A of the General Tax Code provides, as recalled by the Conseil d’État (the supreme administrative court): “Sous réserve des conventions internationales, les plus-values, telles que définies aux e bis et e ter du I de l’article 164 B, réalisées par les personnes et organismes mentionnés au 2 du I lors de la cession des biens ou droits mentionnés au 3 sont soumises à un prélèvement selon le taux fixé au deuxième alinéa du I de l’article 219.” In its decision of 20 June 2023, no. 463599, SCI Faucon, the Conseil d’État applied that levy to a property company held almost entirely by the State of Kuwait after the 2011 sale of a block of flats in Nice, quashed the Court of Appeal’s restitution order, and put the sum of 2,304,487 euros back on the company’s account. The lesson for you is a contrario: that levy is the regime for sellers who are not French tax residents. Because you live in France, your sale is not caught by article 244 bis A at all; it falls under the ordinary resident regime of articles 150 U to 150 VH, which is generally more favourable thanks to the holding-period relief described below. If the French tax office ever applies the non-resident levy to you by mistake — something that happens when a file still shows a London address — the error is frontal and must be challenged immediately.
The second decision shows that treaty wording overrides domestic exclusions. On 12 February 2020, no. 415475, the Conseil d’État dealt with Swiss residents who had sold a Paris building in 2012 and been denied a domestic exemption on the ground that the statute reserved it to French residents. The Court recalled the treaty’s promise that “Les gains provenant de l’aliénation des biens immobiliers, tels qu’ils sont définis à l’alinéa 1er du paragraphe 2 de l’article 6, sont imposable dans l’Etat contractant où ces biens sont situés”, combined with its equal-treatment clause, under which such gains are computed under the same rules regardless of the seller’s State of residence, and concluded that a qualifying Swiss resident could not be shut out of the domestic exemption. The Franco-Swiss treaty is not the Franco-British treaty, but the reasoning method transfers directly: where the 2008 Convention with the United Kingdom allocates a gain to one State or imposes equal treatment, the French administration cannot add a residence condition that the treaty does not contain. Keep that decision in mind if an assessment ever denies you a relief supposedly because the property is abroad — the treaty text, not the property’s postcode, decides.
The third decision belongs to the social-charges chapter and comes from the Cour de cassation (the supreme civil court). On 25 September 2025, Second Civil Chamber, no. 22-24.634, the Court restated the European coordination principle inherited from the De Ruyter case law: the EU regulations “consacrent le principe d’unicité de la législation de sécurité sociale, selon lequel la personne à laquelle les règlements s’appliquent n’est soumise qu’à la législation d’un seul État membre, en sorte que celle-ci, affiliée à un régime de sécurité sociale d’un État membre, ne doit pas contribuer au régime de sécurité sociale d’un autre État membre”. Since 1 January 2021 the United Kingdom is no longer covered by that EU coordination, so a British seller cannot invoke single-legislation protection against French social levies on the gain. Paris has nevertheless preserved one targeted favour, confirmed on the official tax portal (impots.gouv.fr, selling property: tax arrangements and rate): even though the United Kingdom left the European Union on 1 January 2021, British residents affiliated to a compulsory social-security scheme outside France keep the exemption from the CSG and CRDS levies, with a 7.5% solidarity levy still applying. That official position is the Brexit-specific passage to cite in any dispute about the social charges on your sale.
II. How much will France take, and how do you declare and fight the bill?
A. 19% plus 17.2%, year-by-year relief and the main-home trap: how is your French capital-gains bill calculated?
French tax on the sale is really two taxes travelling together. The gain — the plus-value, meaning the sale price minus the purchase price and allowable costs — bears income tax at a flat 19% and social levies (prélèvements sociaux) at an overall 17.2% rate, as the French tax administration confirms for property gains. Both charges then melt away with time, but at different speeds: full income-tax relief after twenty-two years of ownership, and full social-levy relief only after thirty years. The administration’s official tax commentary (BOFIP) sets the yearly pace behind those horizons: for income tax, 6% relief for each year of ownership beyond the fifth up to the twenty-first, then 4% for the twenty-second year; for the social levies, 1.65% per year beyond the fifth up to the twenty-first, 1.60% for the twenty-second year, and 9% per year beyond the twenty-second (BOI-RFPI-PVI-20-20).
A simplified illustration makes the mechanics concrete. Suppose you bought a house near Manchester in 2010 and sell it in 2026, after sixteen full years of ownership, realising a net gain of 150,000 euros once price difference and allowable costs are settled. For income tax, eleven relief years at 6% erase 66% of the gain, leaving 34% taxable: 34% × 19% = 6.46% of the total gain. For the social levies, eleven years at 1.65% erase 18.15%, leaving 81.85% taxable: 81.85% × 17.2% = 14.08% of the total gain. The combined French charge before any treaty credit is therefore about 20.5% of the gain — roughly 30,800 euros on a 150,000-euro gain — and the British tax you have definitively paid on the same gain is then credited against the 19% income-tax portion only, capped at the French income tax attributable to the gain. Two warnings follow. First, the 22-year and 30-year clocks run from the acquisition date under French computation rules, and the Conseil d’État has confirmed that the taxable base is determined “selon les modalités définies” by reference to articles 150 U and 150 V to 150 VD, so keep the original purchase deed, the completion statement and every invoice for works: without proof of the acquisition price and of qualifying expenditure, the administration taxes the full sale price. Second, the social levies are not a single charge but a bundle, and the CSG/CRDS exemption for Britons affiliated to a compulsory scheme outside France does not remove the 7.5% solidarity levy — budget for it.
The most painful trap is the main-home exemption. Article 150 U of the General Tax Code taxes gains realised by individuals “lors de la cession à titre onéreux de biens immobiliers bâtis ou non bâtis ou de droits relatifs à ces biens”, which “sont passibles de l’impôt sur le revenu dans les conditions prévues aux articles 150 V à 150 VH”, but its paragraph II exempts “1° Qui constituent la résidence principale du cédant au jour de la cession” — property that is the seller’s main home on the day of sale. The test is strict and dated: the home must be your principal residence when you sign the final deed, not five years earlier when you lived in it. If you now live permanently in France and rent out or occasionally visit the English house, that house is not your résidence principale, and the exemption is closed to you in France even if the house was your family home for a decade before Brexit. Do not confuse this with the British side either: HMRC’s private residence relief works on occupation history plus the final 9 months, so the same sale can be partly relieved in London and fully taxable in Paris. The reverse configuration — a former French main home sold after departure — obeys different exemption windows and is covered in our guide to selling a French home after moving back to Britain; check which side of the mirror you stand on before claiming anything.
Finally, remember that the gain also feeds your French social-charges base through the general contribution on investment income. Article L. 136-6 of the Social Security Code provides: “Les personnes physiques fiscalement domiciliées en France au sens de l’article 4 B du code général des impôts sont assujetties à une contribution sur les revenus du patrimoine assise sur le montant net retenu pour l’établissement de l’impôt sur le revenu”, including expressly “Des plus-values, gains en capital et profits soumis à l’impôt sur le revenu”. That is the statutory hook for the 17.2% bundle — and the reason the British CSG/CRDS exemption, where available, has to be claimed explicitly rather than assumed. One related classification point matters for mixed histories: article 164 B of the General Tax Code lists as French-source income (“Sont considérés comme revenus de source française”) gains on buildings situated in France — your English house is the exact opposite case, a gain on property outside France realised by a French resident, which is why it is France-as-residence, and not France-as-situs, that taxes it, with the treaty credit doing the anti-double-tax work.
B. Declare in London within 60 days and in Paris on your return: how do you report the sale and challenge double taxation?
Run the two calendars in parallel and never let one wait for the other. On the British side, report the sale to HMRC within 60 days of completion through the UK property-disposal return, even where private residence relief wipes out the liability so that no tax is due, and only the gain accrued since 5 April 2015 is in principle chargeable for a person who is not UK-resident, with relief for qualifying periods of occupation and the final 9 months. Pay the assessed British tax and keep the final computation, because France only credits United Kingdom tax that has been finally assessed and definitively paid on the same gain — A payment on account that is later adjusted is not yet definitive; wait for the final HMRC figure before filing the French claim.
On the French side, declare the worldwide gain on your annual income tax return in the year following the sale, in the capital-gains sections covering foreign-source gains, and attach the British computation with proof of payment. If you arrived in France recently, the same return is also where your residence position is settled for the year — our walkthrough of your first French tax return after Brexit, forms 2042, 2047 and 3916 and the treaty tie-breaker explains how the 2042/2047 architecture captures foreign income, and the capital gain follows the same logic one level further. Compute the French income tax on the gain after holding-period relief, subtract the capped British-tax credit, and pay the social levies with the solidarity-levy adjustment where the CSG/CRDS exemption applies. Keep every document for at least the limitation period: purchase deed and price, sale deed and price, works invoices, letting history, dates of occupation of each home, P60s or French avis d’imposition (tax notices) fixing your residence, and the full HMRC correspondence. Double-tax files are won or lost on paper, years after the removal van has left.
If the French assessment ignores the treaty credit, miscalculates the relief years, denies the CSG/CRDS exemption for Britons, or applies the non-resident levy to a French resident, challenge it in two stages. First, file a written claim (réclamation) with the tax office that issued the notice, identifying the exact error — wrong base, wrong rate, missing credit, missing exemption — and attaching the treaty articles and the HMRC final computation. Most front-line errors are corrected at this stage when the file is complete. If the administration rejects the claim expressly or by silence, appeal to the administrative court (tribunal administratif). Article R. 421-1 of the Code of Administrative Justice sets the frame: “La juridiction ne peut être saisie que par voie de recours formé contre une décision, et ce, dans les deux mois à partir de la notification ou de la publication de la décision attaquée.” You therefore have two months from the rejection to lodge the appeal, and where you seek payment of money the prior claim before the administration is a condition of admissibility — which is why the written réclamation must come first and must ask for exactly what the court action will seek. In court, the three decisions examined above are your arsenal: the 2023 SCI Faucon ruling for the boundary between the resident regime and the non-resident levy, the 2020 ruling for the principle that treaty allocation and equal treatment override domestic residence conditions, and the 2025 Cour de cassation restatement of single-legislation coordination combined with the official impots.gouv.fr confirmation that British residents keep the CSG/CRDS exemption with the 7.5% solidarity levy. Plead them in that order — regime, treaty, charges — and no assessment can survive all three if the facts are properly proved.
Conclusion
A British person living in France who sells a house in England faces two lawful tax claims on one gain: the United Kingdom taxes the bricks where they stand under Article 14 of the 2008 Convention, and France taxes the worldwide gain of its residents under articles 4 A and 4 B of the General Tax Code. The Convention resolves the collision by making France grant a credit for the definitively-paid British tax, capped at the French tax on the same gain. The French charge itself combines 19% income tax melting over 22 years with 17.2% social levies melting over 30 years, subject to the post-Brexit CSG/CRDS exemption for Britons and the surviving 7.5% solidarity levy — and the main-home exemption is unavailable for an English house once your principal residence is in France. Declare in London within 60 days, declare in Paris on the annual return, compute the French base before claiming the capped credit, and challenge any double charge first by written claim and then before the administrative court within two months. Handled in that order, with the deeds and the HMRC computation in the file, the sale of the old English house funds the French life without paying the same tax twice.