You bought a stone cottage in the Dordogne or a seaside flat in Brittany years ago, you live in Manchester or London, and now you want to sell. The French notaire (the public officer who alone can transfer French land) sends you a draft déclaration de plus-value (capital gains return) with two lines of tax that together swallow a third of your profit, plus a demand to appoint a représentant fiscal (accredited tax representative) before the deed can even be signed. Since Brexit, that demand applies to you systematically, and the relief your French neighbours take for granted is closed to you. This article explains, step by step, what France taxes when a British resident sells a French second home, how the gain is calculated, which rates and reliefs truly apply to you, how the sale closes through the notaire and form 2048-IMM, how the United Kingdom taxes the same gain and relieves the French tax, and how to challenge a bill that is wrong. The rules below are those in force for sales completed in 2026.

I. What France taxes when a UK resident sells a French second home

A. How your taxable gain is calculated, and why living in Britain changes nothing about the principle

French tax law starts from a simple proposition. As article 150 U of the General Tax Code puts it: “les plus-values réalisées par les personnes physiques ou les sociétés ou groupements qui relèvent des articles 8 à 8 ter , 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 .”. In plain English: gains on the sale for consideration of built or unbuilt property are subject to income tax. That proposition catches you exactly as it catches a French resident, because the tax follows the land, not the seller. The France–United Kingdom double tax treaty confirms the point. The treaty is, in the words of the Conseil d’État, “la convention entre le gouvernement de la République française et le gouvernement du Royaume-Uni de Grande-Bretagne et d’Irlande du Nord en vue d’éviter les doubles impositions et de prévenir l’évasion et la fraude fiscales en matière d’impôts sur le revenu et sur les gains en capital, signée à Londres le 19 juin 2008”, published by official commentary on the 2008 treaty, and the French tax administration’s official commentary explains that under paragraph 1 of article 14 of the treaty, gains derived by a resident of one State from disposing of immovable property covered by article 6 are taxable in the State where the property stands. France, as the state where your cottage or flat stands, therefore has the first right to tax, and the leading Conseil d’État decision of 12 February 2020, No. 435907, which turns precisely on that 2008 treaty, shows how closely French courts police its interpretation. The United Kingdom may tax the gain as well, but it must relieve the French tax, a mechanism examined in Part II.

The calculation itself follows the ordinary-law method, the droit commun, which the tax administration confirms also applies to non-residents, the base of the gain being determined under ordinary-law conditions. Start with the sale price, the prix de cession, as stated in the deed, then subtract the adjusted acquisition cost, the prix d’acquisition majoré. The acquisition cost is what you paid, plus acquisition expenses. You may take acquisition costs at their real amount, with supporting invoices, or at a statutory flat rate of 7.5% of the purchase price, the forfait de 7,5 %, where no detailed proof exists. Works, the travaux, are the great forgotten line. You may add genuine improvement, construction, reconstruction or enlargement works carried out by a building firm, evidenced by invoices, to your acquisition cost, which directly shrinks the taxable gain. What you cannot add is routine maintenance or repair, nor works you carried out yourself without invoices for materials and labour by a professional. This is where sellers lose thousands. In a judgment of 15 September 2025, the Nice court recorded that “ces déclarations de plus-value étaient erronées, faute pour le notaire d’avoir pris en compte le montant des travaux qu’ils avaient fait réaliser avant la vente”, a dispute over a building of nine flats and a shop where the declared gains ignored the works the sellers had paid for (Tribunal judiciaire de Nice, 15 September 2025, No. 22/04678). Keep every invoice from the day you buy: roof, extension, rewiring by a registered artisan, drainage, swimming pool built by a contractor. Photographs help the notaire understand the file, but only invoices change the arithmetic.

Two points of vocabulary matter before going further. The notaire is not your conveyancer in the English sense. He is a public officer who draws up the deed, calculates the tax, files return No. 2048-IMM and pays the Treasury on your behalf out of the sale price. His calculation binds you in practice: if it overstates the gain, you overpay on the day of the deed and must then claim a refund. The prélèvement is the withholding-style levy collected from non-residents at the time of the deed under article 244 bis A of the General Tax Code, which provides: “L’impôt dû en application du présent article est acquitté lors de l’enregistrement de l’acte ou, à défaut d’enregistrement, dans le mois suivant la cession, sous la responsabilité d’un représentant établi en France, accrédité par l’administration fiscale.” For private individuals the levy discharges your French income tax on the gain; for social charges a parallel collection applies. Because the money leaves your price on completion day, every error in the base or in the holding-period relief costs you cash immediately, which is why the verification routine in Part II starts before you sign anything.

One threshold question first: is your French property really a second home in the French sense? If you moved back to France and genuinely occupy the house as your main home, your résidence principale, on the day of the sale, the gain is fully exempt, resident or not. But the administration is blunt about the reverse: as a non-resident, you cannot claim the exemptions tied to the main home. A British resident who visits six weeks a year cannot claim the main-home exemption, and post-completion occupation by the buyer is irrelevant. If you once lived in the house as your main home and have now left, different windows exist for former main homes, which were covered in a companion piece on leavers and are not this article’s subject. Here, you live in Britain, the house is your holiday home, and the gain is taxable in principle. What remains is to measure it correctly and to pay neither a penny too much nor a day too early.

B. The 19% levy, the 17.2% social charges, the high-gain surtax, and the reliefs a British seller keeps after Brexit

Once the net gain is fixed, three layers of tax can apply, plus holding-period relief that reduces them. First, income tax. The tax administration applies a single 19% levy to gains of private individuals and partnerships after reliefs, and the English version of the service-public fact sheet confirms the same 19% rate on the gain after deduction of the allowance or allowances. For a taxable gain of 100,000 euros, that is 19,000 euros of income tax. This 19% rate is the same for you as for a French resident, and Brexit did not change it: companies pay a different rate, but private sellers pay 19%.

Second, the social charges, the prélèvements sociaux: CSG, CRDS and solidarity levies bundled together. The current published position is clear: social charges apply at the overall rate of 17.2%. On the same 100,000 euros, that is 17,200 euros. British sellers sometimes ask whether years of National Insurance contributions in the UK exempt them, or whether an S1 healthcare certificate changes the answer. For a UK resident selling a French second home, the answer is no: the 17.2% applies to the gain regardless of your British social security record. Older pages on the impots.gouv.fr site still display a 15.5% figure dating from 2016; do not rely on it. The 17.2% rate is the one the notaire will apply in 2026, and any deed calculated at 15.5% is simply wrong in your favour and will be corrected by the administration with interest.

Third, the surtax on large gains, the taxe sur les plus-values immobilières élevées. Where the net taxable gain exceeds 50,000 euros, an additional progressive levy of 2% to 6% bites on the fraction above the threshold. On a gain of 200,000 euros the surtax runs to several thousand euros, and sellers who budget only for 19% plus 17.2% are caught short on completion day. Ask the notaire for a written simulation showing all three layers before you commit to a sale price, because the surtax, unlike the main levy, is easy to overlook and impossible to renegotiate once the deed is signed.

Against these layers stand the holding-period reliefs, the abattements pour durée de détention, which reward patience and eventually erase the tax. For income tax, relief accrues year by year and produces full exemption after 22 years of ownership: 6% per year from the sixth to the twenty-first year, then 4% for the twenty-second year. For social charges, the clock runs slower: 1.65% per year from the sixth to the twenty-first year, 1.6% for the twenty-second, then 9% per year beyond, giving full exemption after 30 years. The service-public guidance summarises the endpoints: no more income tax once the property has been held for over 22 years, and no more social charges once it has been held for over 30 years. Two small sales escape tax altogether outside any holding period: disposals of 15,000 euros or less are exempt, and that threshold is assessed per property, not per seller. Check the holding period from the date of the acquisition deed to the date of the sale deed, counting full years, and verify the notaire’s table line by line. The Paris Court of Appeal has already condemned a notaire precisely for this kind of mistake: “le notaire a omis de déduire, dans la déclaration de plus-value, l’abattement de droit commun pour la durée de détention prévue à l’article 150 VC du code général des impôts”, holding that “Dit que M. [A] [H], notaire exerçant au sein de la Scp [2], a commis une faute en sa qualité de rédacteur d’acte” (Paris Court of Appeal, 7 April 2026, No. 22/19262). If a Paris notaire can misapply the standard relief, any notaire can, and only your own check protects you.

Now the Brexit sting: the one-off 150,000-euro relief for non-residents is closed to you. French law offers certain leavers a special exemption of up to 150,000 euros of net gain on a French dwelling, but article 150 U, II, 2° reserves it to a seller who is “ressortissante d’un Etat membre de l’Union européenne ou d’un autre Etat partie à l’accord sur l’Espace économique européen ayant conclu avec la France une convention d’assistance administrative en vue de lutter contre la fraude et l’évasion fiscales et à la condition qu’il ait été fiscalement domicilié en France de manière continue pendant au moins deux ans à un moment quelconque antérieurement à la cession”. A British citizen resident in the UK is neither an EU nor an EEA national, so the provision cannot apply, however long you once lived in France. The impots.gouv.fr site says the same in plainer terms, limiting the relief to sellers who are nationals of an EU or EEA state. Do not let anyone promise you this relief on the strength of pre-Brexit advice found online. Equally, property held through a company, a société civile immobilière (SCI, the French family property company), is taxed under different rules and is outside this article: the rates and the representative mechanism differ, and the 19% individual rate does not automatically carry over.

A worked example fixes the ideas. Suppose you bought a Dordogne cottage in June 2014 for 220,000 euros, paid 16,500 euros of acquisition costs, and had a registered builder extend the kitchen in 2017 for 28,000 euros invoiced. Your adjusted base is 264,500 euros. You sell in October 2026 for 420,000 euros. The gross gain is 155,500 euros. Held for 12 full years, the income-tax relief is 6% times 7 years, or 42%, leaving 90,190 euros taxable at 19%, or 17,136 euros. The social-charges relief is 1.65% times 7, or 11.55%, leaving 137,540 euros taxable at 17.2%, or 23,657 euros. The surtax applies because the net gain exceeds 50,000 euros. Total French tax: roughly 43,000 euros before the surtax. Change one input, omit the 28,000 euros of works, and you add over 10,000 euros of tax. Sell after 22 years instead, and the income-tax layer vanishes while social charges survive until year 30. Every line of the return is money, and every line is checkable.

II. How the sale closes in practice, and how to fight a bill that is wrong

A. The notaire, form 2048-IMM, the accredited representative you must appoint, and the British credit that avoids double tax

The sale closes in one meeting, but the tax work starts weeks before. Your compromis de vente, the preliminary contract, fixes the price and the timetable. Between the compromis and the acte authentique, the final deed signed before the notaire, the notaire prepares return No. 2048-IMM, computes the three tax layers, and deducts them from the price. You receive the net proceeds; the Treasury receives its share the same day. Insist on receiving the draft 2048-IMM at least two weeks before completion, with the detailed table: gross price, adjusted base with each invoice listed, holding-period percentages for income tax and for social charges, surtax computation, and the resulting deductions. Compare every figure with your own file. The Bordeaux court shows what happens when the information comes too late: a seller who learned the tax cost only when she could no longer walk away sued her notaire for breach of the duty to advise, and the court awarded her 25,247 euros, holding “CONDAMNE Maître [J] [U] à payer à Mme [H] [I] la somme de 25.247 euros en réparation de la perte de chance subie du fait du manquement à l’obligation de conseil sur la fiscalité sur la plus value applicable à la cession de sa parcelle DL [Cadastre 3] de [Localité 14] (33)” (Tribunal judiciaire de Bordeaux, 18 March 2025, No. 23/00043). Late information is a fault, and the fault has a price, but you would rather have the right figure before the deed than damages years later.

Because you live in Britain, you must in most cases appoint a représentant fiscal, an accredited tax representative established in France who guarantees the tax and signs the return alongside the notaire. The statute is explicit: “L’impôt dû en application du présent article est acquitté lors de l’enregistrement de l’acte ou, à défaut d’enregistrement, dans le mois suivant la cession, sous la responsabilité d’un représentant établi en France, accrédité par l’administration fiscale” (article 244 bis A, IV). The exemption from this duty covers only sellers “domicilié, établi ou constitué dans un Etat membre de l’Union européenne ou dans un autre Etat partie à l’accord sur l’Espace économique européen”, and since 1 January 2021 the United Kingdom is neither. In practice the administration requires sellers not domiciled in an EEA State, Liechtenstein apart, to appoint a representative wherever the sale price exceeds 150,000 euros. Below that price the duty is lighter, but most second homes in the south-west, Brittany, Normandy and Paris exceed it. Two practical warnings follow. First, your notaire cannot act as your representative: budget separately for an accredited company, usually a specialised firm charging a percentage of the gain or a fixed fee, and engage it as soon as the compromis is signed, because accreditation checks take time and completion cannot proceed without the representative’s signature. Second, the representative’s fee is not deductible from the gain; it is a cost of the procedure, to be weighed against the price, not against the tax.

On the British side, His Majesty’s Revenue and Customs taxes you too, then relieves the French tax. The official guidance is short: UK residents pay Capital Gains Tax when disposing of overseas property, tax may also be due in the country where the gain arose, and double taxation may be relieved on claim (GOV.UK, Tax when you sell property: selling overseas property). In practice you report the French sale on your UK Self Assessment return, compute the UK gain under UK rules, which differ from French rules on costs, reliefs and private residence relief, and claim Foreign Tax Credit Relief for the French income tax, up to the amount of UK tax due on the same gain. Keep the French deed, the 2048-IMM, and proof of payment: HMRC will want them. Note the asymmetry that traps the unwary. The UK gives no credit for the French social charges as such; only the French income-tax layer counts toward the credit, and any excess French tax is lost. Timing also differs: French tax leaves the price on completion day, while UK tax follows the tax year. Plan cash flow for both, and take British advice on the UK computation in parallel with the French file, because an error on either side is paid in full before any relief arrives.

Paris and Île-de-France sellers face one extra wrinkle worth knowing. Where the property stands in Paris, the representative’s accreditation and the property-tax office sit with the Paris regional tax directorate rather than a local office, and notaires in the capital routinely require the representative’s file a full month before completion. If your flat is in the 7th arrondissement or your house in the Yvelines, tell the representative the Paris address at the first call: routing the file to the wrong office is the commonest avoidable cause of postponed completions in high-season sales.

B. The errors that inflate the bill, and the remedies that bring money back

Five errors account for most overpayments, and each has a remedy. First, forgotten works. Builders’ invoices left in a drawer are the classic loss, as the Nice case above demonstrates. Remedy: assemble every invoice before the compromis, hand the bundle to the notaire with a dated inventory, and have the works line acknowledged in writing in the draft return. Second, misapplied holding-period relief. The Paris 2026 decision proves the risk is real even in sophisticated offices. Remedy: recompute the full years of ownership yourself from the two deeds, apply the income-tax scale and the social-charges scale separately, and demand correction of the draft before signing. Third, the wrong exemption claimed or the right one missed. Some sellers still invoke the former main-home windows or the 150,000-euro leavers’ relief after moving back to Britain years ago; others miss the 15,000-euro small-sale exemption or the 22- and 30-year endpoints by months and sell too early. Remedy: date the completion deliberately. Where the twenty-second anniversary falls weeks after the planned deed, postponing completion can erase the entire income-tax layer lawfully. Fourth, the missing representative or the wrong one. A deed signed without the required representative exposes the seller to penalties and blocks registration; a representative engaged without checking accreditation wastes fees. Remedy: verify accreditation with the property-tax office of the place where the property stands before paying any retainer. Fifth, double tax accepted without claiming the British credit. Some sellers pay in France and then omit the foreign-tax claim in Britain, paying twice in full. Remedy: file the UK return with the credit claim and keep French proofs for six years.

Where the deed is already signed and the tax already paid, French law gives you a genuine second chance: the réclamation contentieuse, the formal tax claim. The deadline rule is generous but strict: it generally expires on 31 December of the second year following the year the tax was put into collection, as shown on the tax notice. For a gain taxed through the deed in 2026, that ordinarily means 31 December 2028. File online from your personal space on impots.gouv.fr or by recorded letter to the property-tax office, identifying the deed, the 2048-IMM, the precise error with exhibits, and the exact refund sought. The administration has six months to answer; silence for six months is an implied rejection that opens the door to the administrative court, the tribunal administratif, within two further months. Frame the claim narrowly around demonstrable arithmetic: omitted invoices, miscounted years, misapplied scale, surtax wrongly computed. Broad complaints about Brexit or about the level of French tax go nowhere; a one-page table with deeds and invoices attached wins refunds. Where the fault lies with the notaire rather than with the Treasury, the civil courts offer the parallel route illustrated by the Nice, Bordeaux and Paris decisions: an action for breach of the duty to advise and of the duty of care in drawing up the deed, seeking damages equal to the overpaid tax and the lost chance of selling on better terms. Time limits for professional liability are short in effect, so put the notaire on notice in writing as soon as the error surfaces and have the file reviewed before the tax-claim deadline expires.

One final trap deserves its own paragraph because it surprises British sellers more than any other: the price itself. French tax is computed on the deed price, and the administration may challenge an understated price by reassessment, the rehaussement, comparing it with comparable sales. Conversely, an overstated allocation of furniture, the mobilier, deducted from the property price to shrink the gain, attracts the same scrutiny. Keep the estate agent’s valuation, the listing history, and the inventory of furniture with second-hand values. A clean price file defeats a reassessment before it starts; a price arranged over lunch invites one.

Conclusion

Selling a French second home from Britain after Brexit is a two-country operation with a single moment of truth: the deed before the notaire. France taxes first, at 19% plus 17.2% plus any surtax above 50,000 euros of gain, with relief that grows with ownership until 22 years for income tax and 30 years for social charges, and without the 150,000-euro leavers’ relief that Brexit closed to British nationals. The United Kingdom taxes second and credits the French income tax. The representative, the 2048-IMM, and the invoice bundle decide whether you pay the right amount on the day; the formal claim and, where needed, the action against the notaire decide whether an error stays permanent. Prepare the file as this article describes, check the draft return line by line, and calendar the claim deadline the day you sell. The French house gave you years of holidays; with method, its sale need not give you years of regret.

Need a quick opinion on your case?

Selling a French second home from the UK, or challenging a capital gains bill that looks wrong? Telephone consultation: 80 EUR TTC, within 48 hours, with an avocat of the firm. Call +33 6 46 60 58 22 or write via our contact page. For Paris and Île-de-France properties, we handle the notaire’s draft return, the accredited representative, and any claim before the French tax administration.