You moved to France after Brexit, became French tax resident, and kept your house in England. Years later you sell it. The conveyancer in England completes the sale, the money lands in your account, and you assume the story ends there. It does not. France taxes you on that gain as well, and the French bill often comes as a shock: income tax at a flat rate, plus social charges, computed under French rules on a sale that happened entirely abroad. The good news is that the France–United Kingdom double tax treaty of 19 June 2008 stops you paying twice, through a tax credit for the British capital gains tax you have already paid. The bad news is that the credit is capped, the paperwork sits entirely on your shoulders, and the two tax authorities do not talk to each other. This article explains, step by step, how the French tax on your English house sale is built, how the treaty credit works, and how to challenge the French assessment if it goes wrong. What follows maps the French computation, then the treaty relief, then the remedies, in that order.

French tax law starts from a simple principle: once you are French tax resident, France taxes your worldwide income and gains. Article 4 A of the French General Tax Code (Code général des impôts, the CGI) provides that “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.” Your domicile for tax purposes (domicile fiscal) is in France, under Article 4 B of the CGI, if France is where you have your home or your principal place of stay (foyer ou lieu de séjour principal), or where you carry on your professional activity. If you live year-round in France, you meet that test even though you hold a British passport and even though the property you sell stands in England. Readers unsure about their residence position should read our analysis of the Franco-British tie-breaker rules first: British Dual Tax Residence and the France–UK Tie-Breaker.

I. France Taxes Your English House Sale Under French Property-Gains Rules

A. How France Brings a Foreign Sale Into French Income Tax

French law treats the sale of your English house as an ordinary private property gain (plus-value immobilière des particuliers). Article 150 U of the CGI provides that “les plus-values réalisées par les personnes physiques […] lors de la cession à titre onéreux de biens immobiliers bâtis ou non bâtis ou de droits relatifs à ces biens, sont passibles de l’impôt sur le revenu dans les conditions prévues aux articles 150 V à 150 VH”. Nothing in that wording limits the rule to property located in France: a house in Manchester, Bristol or London sold by a French tax resident falls squarely within it. The mirror image confirms the logic: people who are not French tax resident and sell French property face a separate withholding levy under Article 244 bis A, as the Conseil d’État (France’s supreme administrative court) recalled when it held that “les personnes physiques et morales qui ne sont pas résidentes de France sont soumises au prélèvement […] sur les plus-values résultant de la cession” of buildings (CE, 16 May 2018, no. 398055, full decision on Légifrance). You are on the other side of that line: resident in France, selling abroad, taxed in France on the worldwide gain.

Two common misunderstandings need clearing up at once. First, the main-home exemption does not save you. Article 150 U exempts buildings “Qui constituent la résidence principale du cédant au jour de la cession” (Article 150 U of the CGI) — property that is your main home on the day of sale. Your English house is not your main home if you live in France; it is at best a former main home or a second home, and the exemption for a first sale by someone who does not own their main home comes with strict reinvestment conditions that rarely fit this scenario. Second, Brexit changed nothing about this mechanism. The rule flows from French domestic law, not from European Union membership, and it applies to British sellers exactly as it applies to French residents selling a holiday flat in Spain or a flat in New York.

The starting figure — the gross gain (plus-value brute) — follows Article 150 V of the CGI: “La plus ou moins-value brute réalisée lors de la cession de biens ou droits mentionnés aux articles 150 U à 150 UC est égale à la différence entre le prix de cession et le prix d’acquisition par le cédant.” Sale price minus purchase price. In practice, French law then adjusts each side: the purchase price can be increased by acquisition costs (fixed allowances or actual notaire fees on purchase) and by substantiated improvement works, while the sale price is reduced by the costs of disposal such as estate-agent fees. Keep every invoice and the English completion statement: the French tax office (service des impôts des particuliers) will want documentary proof, in euros, of each figure. Convert sterling amounts using a consistent, documented rate and keep the calculation, because the inspector will check it.

B. The French Bill: 19 Percent Tax, Social Charges, and Relief That Grows With Time

Once the gross gain is set, France applies its standard machinery for private property gains. Article 200 B of the CGI provides that “Les plus-values réalisées dans les conditions prévues aux articles 150 U à 150 UC sont imposées au taux forfaitaire de 19 %.” That 19 per cent is a flat rate of income tax, applied to the gain after the holding-period relief described below — not to the sale price. It is only the first layer. French social charges (prélèvements sociaux) form the second layer, currently 17.2 per cent in total. Their legal base is Article L. 136-6 of the Social Security Code, which provides that “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”, expressly including “Des plus-values, gains en capital et profits soumis à l’impôt sur le revenu” (Article L. 136-6 of the Social Security Code). Your English house gain is exactly that: a capital gain subject to income tax, so it feeds the social-charges base as well.

The relief that reduces both layers depends purely on how long you owned the property, and the official tax doctrine states the current scale word for word. For income tax, the French tax administration’s published doctrine grants, for income tax, relief of 6 per cent for each year of ownership beyond the fifth and up to the twenty-first, plus 4 per cent for the twenty-second year, so that full income-tax exemption is reached after twenty-two years of ownership (BOI-RFPI-PVI-20-20). For social charges the scale runs slower: 1.65 per cent per year beyond the fifth and up to the twenty-first, 1.60 per cent for the twenty-second year, then 9 per cent per year beyond, with full exemption reached only after thirty years (same source). So a house bought in 2010 and sold in 2026 — sixteen full years of ownership — earns ten years of relief: 60 per cent off the income-tax base, but only 16.5 per cent off the social-charges base. The holding period normally runs from the acquisition deed to the sale, and co-owners are treated individually, so check each owner’s dates.

A short worked example shows how the two layers interact. Take a house bought for £200,000 in 2010 and sold for £320,000 in 2026, with £10,000 of documented acquisition costs and £5,000 of estate-agent fees, converted to euros at a consistent rate. The gross gain is roughly €130,000 before conversion effects. Sixteen full years of ownership give ten years of relief beyond the fifth: the income-tax base falls by 60 per cent to about €52,000, taxed at 19 per cent, or roughly €9,900. The social-charges base falls by only 16.5 per cent to about €108,500, charged at 17.2 per cent, or roughly €18,700. The British capital gains tax actually paid is then credited against the French income-tax portion up to its amount — never against more than France charged — while the social-charges portion follows the treaty-credit analysis explained below. Change any input — a shorter holding period, missing invoices, an undeclared gain — and the French bill moves sharply, which is why documentation decides these files.

A practical warning particular to foreign sales: no French notaire (the public officer who normally computes, collects and pays the tax on French sales) is involved in an English conveyance. Nobody withholds the French tax at completion. The whole French liability is self-assessed on your French income tax return the year after the sale. Article 170 of the CGI requires that “toute personne imposable audit impôt est tenue de souscrire et de faire parvenir à l’administration une déclaration détaillée de ses revenus et bénéfices”, and the French tax administration instructs taxpayers with foreign-source income to complete schedule 2047 first, together with forms 2042 and 2042C (impots.gouv.fr, taxation of foreign-source income). File the 2047 foreign-income schedule together with your main 2042 return, report the gain and the British tax paid, and claim the treaty credit there. Miss the return and the administration will assess you late, with interest and penalties, on figures of its own choosing.

II. The Treaty Credit Wipes Out Double Taxation, and You Can Fight a Wrong Assessment

A. What the France–UK Treaty Gives You: UK Tax First, French Credit Second

Both countries claim the gain: the United Kingdom because the house stands on its soil, France because you live on French soil. The treaty divides the work. Its capital-gains article gives the state where the property stands the primary right to tax the gain on its sale, and the French tax administration’s commentary confirms the rule for Franco-British sales (BOI-INT-CVB-GBR-10-20 on gains en capital). In plain terms: the UK keeps the primary right to tax the sale of an English house, and France must eliminate the resulting double taxation. The French tax administration’s commentary on the treaty confirms that where the gain may be taxed by the non-residence state under Article 14, it is for the residence state — here France — to eliminate the double taxation (BOI-INT-CVB-GBR-10-20).

The elimination method for this kind of gain is a credit equal to the British tax, capped at the French tax. The treaty text, reproduced in the Conseil d’État‘s opinion, states that for gains covered by paragraphs 1, 2 and 6 of Article 14 the credit equals “au montant de l’impôt payé au Royaume-Uni conformément aux dispositions de ces articles ; toutefois, ce crédit d’impôt ne peut excéder le montant de l’impôt français correspondant à ces revenus” (CE, advisory opinion, 12 February 2020, no. 435907). The general published doctrine describes the same mechanism as a credit equal to the tax paid in the other state on the foreign-source income, capped at the French tax computed on that same income (BOI-INT-DG-20-20-100). Two consequences follow. If the British tax equals or exceeds the French tax on the same gain, the French income-tax liability on that gain falls to zero. If the British tax is lower — for example because British reliefs sheltered part of the gain — France collects the difference. France never refunds the excess when British tax is higher; the cap works one way only.

That same Conseil d’État opinion secures two further points that regularly decide real files. First, the credit also covers French social charges, which form part of the French tax under the treaty, and the Conseil d’État held that “aucune stipulation de l’article 24 ne subordonne l’octroi d’un crédit d’impôt égal à leur montant à ce que les revenus soumis à ces contributions aient été compris dans la base d’un impôt équivalent ou similaire au Royaume-Uni” (CE, advisory opinion, 12 February 2020, no. 435907, point 6). Second, the door stays open even when little or no British tax was actually paid: the Conseil d’État held that “cette condition n’exige pas que les revenus en cause aient été soumis à une imposition effective” (CE, advisory opinion, 12 February 2020, no. 435907, point 6), and that declaring the income in the United Kingdom suffices “alors même qu’il n’aurait acquitté dans cet Etat aucun impôt à raison de ces revenus” (same opinion, point 7). In practice this means: always file the British return and declare the gain there, even if British reliefs reduce the UK bill to nothing, because that declaration protects your French credit position. For completeness on the British side, His Majesty’s Revenue and Customs requires UK residential-property disposals to be reported with any tax paid within 60 days of completion, with interest and penalties for late filing and payment (gov.uk, reporting UK property sales). That sixty-day British deadline runs long before the French return is due, so diarise it from completion day.

One final treaty trap deserves attention from readers who moved recently. The convention also preserves each contracting state’s right, under its domestic law, 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 six preceding tax years, a tail that recent arrivals from Britain should check before exchanging contracts (BOI-INT-CVB-GBR-10-20 on gains of former residents). In other words, a Briton who left the United Kingdom for France only a few years ago can face a residual British claim alongside the French charge, with its own elimination mechanics. Long-settled French residents are unaffected, but recent arrivals should take coordinated advice in both countries before exchanging contracts.

Do not confuse this scenario with its mirror image. If you had left France for Britain and then sold a French property, different treaty windows and the non-resident levy would apply — see our guide to selling a former French home after leaving for Britain. And if you kept the English property and let it out instead of selling, the rental income follows its own treaty path, explained in our guide to UK rental income received while living in France.

B. When the French Assessment Is Wrong: Reply, Claim, and Go to Court

Disputes follow familiar patterns: the inspector refuses the treaty credit, computes the holding relief from the wrong start date, converts sterling at an unfavourable rate, or taxes a gain that belongs to a different year. Your first shield arrives by post. Livre des procédures fiscales (the LPF) provides that “L’administration adresse au contribuable une proposition de rectification qui doit être motivée de manière à lui permettre de formuler ses observations ou de faire connaître son acceptation” (Article L. 57 of the LPF), and the same article extends the reply period by thirty days on request made before expiry (“ce délai est prorogé de trente jours”). Never let that notice go unanswered: reply in writing, within the stated period, attaching the English completion statement, the purchase deed with acquisition costs, the holding-period calculation, the British tax return with proof of payment, and the treaty-credit computation. Many files are won at this stage, before any formal claim.

If the assessment stands, the formal claim (réclamation contentieuse) is your next step. Article L. 190 of the LPF sends to the courts claims seeking “soit la réparation d’erreurs commises dans l’assiette ou le calcul des impositions, soit le bénéfice d’un droit résultant d’une disposition législative ou réglementaire” — exactly a refused treaty credit or a miscomputed gain. The deadline is strict: Article R.*196-1 of the LPF requires claims to be filed “au plus tard le 31 décembre de la deuxième année suivant celle” of the recovery notice, the tax payment where no assessment notice exists, or the event giving rise to the claim. A claim filed on 2 January instead of 31 December is out of time, and no argument on the merits will save it — so file early, by recorded delivery or through your online tax account (messagerie sécurisée), and keep the receipt. If the administration rejects the claim expressly or stays silent for six months, you may take the case to the administrative court (tribunal administratif), where the treaty wording and the Conseil d’État opinion quoted above carry full weight.

Three file-building habits make the difference between winning and losing. First, prove the British tax with primary documents: the UK property return, the payment reference, and the self-assessment computation — the credit equals tax paid in the UK, so every pound documented is a euro of French credit up to the cap. Second, prove the dates: purchase deed, completion statement, and any periods the property was your main home, because the holding relief and the British reliefs both turn on precise chronology. Third, keep the exchange-rate trail: one published source applied consistently to acquisition and disposal figures, stated in the return. With those three bundles, the treaty does the rest of the work.

Conclusion

Selling your English house while living in France means two tax systems share one gain: the United Kingdom taxes it as the country where the property stands, under Article 14 of the 2008 treaty, and France taxes it as the country where you live, under Articles 4 A, 150 U and 200 B of the CGI plus social charges — with holding-period relief softening the French bill after five years and extinguishing the income-tax layer after twenty-two. The treaty prevents double taxation through a French credit equal to the British tax paid, capped at the French tax on the same gain, a mechanism the Conseil d’État has confirmed extends to social charges without requiring equivalent British charges or even effective British taxation. Meet the British sixty-day reporting deadline, declare the gain on forms 2047 and 2042-C the following year, document every figure, and answer any French rectification proposal on time. Handled in that order, an English sale from a French home ends not with double tax, but with each country taking only its treaty share.