You have lived in France since Brexit, you still hold shares listed in London — perhaps BP, HSBC, Unilever or a FTSE tracker built up over decades — and this year you sold a tranche to fund works on your French house, help your children or simply simplify your life. Your UK broker has sent a consolidated tax certificate, your French avis d’imposition (income tax assessment) season is approaching, and one question keeps you awake: will France tax the gain, will the United Kingdom tax it too, and which form stops you paying twice? The short answer is that France normally taxes the worldwide gains of its residents, the France–United Kingdom treaty of 19 June 2008 normally reserves ordinary listed-share gains to your state of residence, and your protection lies in the arithmetic of the gain, the correct annexes to your French return, and a challenge filed on time if the bill is wrong. This article explains, for a British reader, every French term at first use, with the official texts and two court decisions quoted word for word.
Three misunderstandings cause most of the damage seen in practice. The first is the belief that because the shares sit in a UK account, in sterling, with a UK broker, only the United Kingdom can tax the sale. French residence does not work that way: once you are a French tax resident, France taxes gains on shares wherever the company and the account are located. The second is the mirror error: assuming that because HM Revenue and Customs (HMRC, the UK tax authority) automatically deducted nothing or applied the annual exempt amount, nothing is due anywhere. The United Kingdom may indeed take nothing on a non-resident, while France takes the full charge plus the prélèvements sociaux (social surcharges on capital income). The third is procedural: declaring the cash received rather than the computed net gain, on the wrong form, with no broker schedule attached, which invites a proposition de rectification (formal notice that the tax office intends to reassess you) a year later. Each of these traps is avoidable once the residence rule, the calculation rule and the treaty rule are set out in order.
I. Do I Pay French Tax When I Sell My UK Shares as a French Resident After Brexit?
A. Am I a French Tax Resident on the Day I Sell My London Shares?
Everything turns on one preliminary question: were you domiciled in France for tax purposes (domicile fiscal) in the year of the sale? Article 4 A of the French Tax Code (Code général des impôts) states the worldwide principle in one sentence: “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.” In plain English, a French tax resident pays French impôt sur le revenu (income tax) on all income and gains, French-source and foreign-source alike. A person whose tax domicile is outside France pays French tax only on French-source income, a category defined separately by Article 164 B of the same Code, which lists, among others, income from buildings situated in France and income from French securities. Your London-listed shares are not French-source property in that sense, so a person who is genuinely non-resident of France has no French charge on them — but a person who is resident does, on the whole gain.
Residence itself is tested against three alternative criteria in Article 4 B of the Tax Code: the foyer (family home) or principal place of stay in France, professional activity carried on in France unless it is merely ancillary, and the centre of economic interests in France. Meeting any one of the three is enough. For most British settlers the analysis is straightforward: a couple whose main home is in the Dordogne, whose children attend a French school and who spend ten months a year there has its foyer in France even if one spouse still travels to London for board meetings. A retired person with no professional activity is still resident through the home test and usually through the centre-of-interests test, since the main house, the French bank accounts, the assurance-vie (a French-regulated savings and life policy) and daily life are all in France. Conversely, a second-home owner who spends eight weeks a year in Provence, keeps family, work and banking in Manchester, and remains UK resident under the treaty tie-breaker is not French resident merely because a French house exists.
The same Article 4 B adds a treaty safety valve that many readers miss: “Les personnes qui satisfont à l’un au moins des critères fixés aux a à c du présent 1 ne peuvent toutefois pas être considérées comme ayant leur domicile fiscal en France lorsque, par application des conventions internationales relatives aux doubles impositions, elles ne sont pas regardées comme résidentes de France.” In other words, domestic criteria come first, but the treaty has the last word where both States claim you. The administrative courts apply exactly this two-stage method. In a leading judgment on gains and treaties, the Conseil d’État (France’s supreme administrative court) held: “Si une convention bilatérale conclue en vue d’éviter les doubles impositions peut, en vertu de l’article 55 de la Constitution, conduire à écarter, sur tel ou tel point, la loi fiscale nationale, elle ne peut pas, par elle-même, directement servir de base légale à une décision relative à l’imposition.” The judge first asks whether French domestic law validly establishes the charge and on what classification, then asks whether the treaty blocks it. For your share sale, that means the Direction générale des Finances publiques (DGFiP, the French tax administration) will first assert worldwide taxation under Articles 4 A and 4 B, and only then will the France–United Kingdom treaty be examined to see whether the United Kingdom alone, France alone, or both may tax.
Practical consequences follow for timing. Residence is assessed year by year, and the year of the disposal counts. A British national who moves to France in March, sells a large UK portfolio in October of the same year and argues the shares were “acquired while British” will normally lose: the gain arose in a year in which the seller was French resident, so the full gain falls within the French charge, subject only to treaty relief. Splitting the family — one spouse moving early, the other remaining in Kent until a UK house sale completes — does not split the household for the foyer test if the family home has in substance moved. Keeping a detailed timeline matters: tenancy agreements, school certificates, travel records, utility bills and the date of inscription au consulat (consular registration) all help prove or disprove where the principal stay lay. Newcomers who want the full first-year picture should read our companion guide to your first French tax return after moving from the United Kingdom, covering Forms 2042, 2047 and 3916 and the treaty tie-breaker, before tackling the share schedules described below.
One further residence trap deserves emphasis because it is peculiar to share gains. Article 14(6) of the France–United Kingdom treaty, discussed in detail in Part II, preserves for six fiscal years the former State’s right to tax gains of a person who was its resident at any time during the previous six years. A British family that leaves France for Surrey and sells a portfolio eighteen months later may therefore face a French claim as well as a UK one, with elimination mechanics deciding who ultimately keeps the tax. Keep departure evidence — lease end, removal invoices, school leaving certificates, UK council tax bills — with the same care as arrival evidence. And note the mirror image in French domestic law: Article 244 bis B of the Tax Code imposes a withholding charge on gains of non-residents only where the seller’s family group held more than 25 per cent of a company’s profits at any time in the previous five years — a substantial-participation test that rarely touches ordinary holders of listed shares but can surprise a former founder who kept a large stake in a private company. Ordinary FTSE holdings sold while you live in Lyon or Bordeaux fall under the resident regime, not this one, but the provision shows why the administration always asks first about the size of your holding.
B. How Does France Calculate and Tax My Gain on UK Shares?
Once residence is settled, French law classifies the profit as a plus-value de cession de valeurs mobilières (gain on the disposal of securities). Article 150-0 A of the Tax Code charges “les gains nets retirés des cessions à titre onéreux, effectuées directement, par personne interposée ou par l’intermédiaire d’une fiducie, de valeurs mobilières, de droits sociaux” — net gains on sales for consideration, made directly, through an intermediary or through a trust, of securities and company rights. London-listed ordinary shares, investment-trust shares, exchange-traded funds and most UK fund units held in a general investment account all fall within this language. Gifts, inheritances and transfers into a trust without consideration are not sales within this article; they belong to the registration-duty and no-consideration transfer rules instead. A bed-and-breakfast sale and repurchase, a transfer between your own nominee accounts without change of beneficial ownership, or a corporate reorganisation exchanging shares for shares may each receive specific treatment, but a straightforward sale of Vodafone or AstraZeneca shares for sterling credited to your broker account is squarely a chargeable disposal.
The computation is set by Article 150-0 D of the Tax Code: “Les gains nets mentionnés au I de l’article 150-0 A sont constitués par la différence entre le prix effectif de cession des titres ou droits, net des frais et taxes acquittés par le cédant, et leur prix effectif d’acquisition par celui-ci” — sale price net of the seller’s costs and taxes, minus effective acquisition price. Every element of that sentence is litigated in practice, so build the file as a litigator would. Sale price means the sterling consideration converted into euros at the exchange rate on the disposal date, less broker commission, stamp duty reserve tax borne as seller where applicable, and transfer fees. Acquisition price means what you actually paid — subscription price, exercise price plus amount paid for options, or market value used for death or gift duties where you inherited — less any investment-related income-tax reductions already obtained, and adjusted for corporate actions. Rights issues, bonus issues, splits, consolidations, takeovers paid partly in shares and dividend reinvestment plans all change the per-share base cost; the DGFiP expects a share-by-share history, not a single remembered figure. Where you inherited the shares, the base is the value retained for succession duties (droits de mutation), so retrieve the UK probate valuation and the French declaration if one was filed.
Losses follow the same article and are frequently wasted by British sellers who do not know the French rule. Capital losses on shares are charged against gains of the same nature in the same year, and any excess may be carried forward for ten years against later share gains only — never against salary, pensions or rental income, and never repaid. A year in which you realise a £40,000 gain on Unilever and a £25,000 loss on a speculative AIM stock therefore yields a £15,000 net taxable base, provided both are properly returned. But a loss crystallised in a year when you file nothing, because “there was no overall profit”, is lost unless the annex recording it was filed: the carry-forward must be tracked on the imprimé 2074 (the dedicated capital-gains schedule, Form 2074) each year, with the unrelieved balance brought forward. Keep contract notes, corporate-action notices, subscription statements and the annual broker tax report for at least the reassessment period plus the carry-forward horizon. The Cour de cassation (France’s supreme civil court) regularly reminds taxpayers that claimed exemptions and reliefs must be proved with documents; in one share-sale dispute it endorsed a court of appeal which had held that the asserted exemption on the gain was unfounded and that the taxpayer, duly informed, had held an alternative course open to him — reasoning that underlines how French judges treat an unproved or misclassified claim on a disposal.
The rate structure then surprises many British readers twice over. Since 2018, gains within Article 150-0 A fall by default under the prélèvement forfaitaire unique (PFU, the single flat-rate levy, often called the flat tax): “Le taux forfaitaire mentionné au premier alinéa du présent 1 est fixé à 12,8 %” for income tax, to which are added the prélèvements sociaux at a combined 17.2 per cent, giving an all-in 30 per cent on the net gain before any treaty credit. The PFU is not a withholding operated by your UK broker; it is charged through your French assessment after you return the gain. You may elect instead for the progressive scale (barème progressif) — the election is global for all investment income and gains of the household for the year — which taxes the gain at your marginal income-tax rate with social surcharges still due, and which can suit households with little other income or with surviving pre-2018 holding-period allowances (abattements pour durée de détention) on shares acquired before 1 January 2018. Those allowances, where available, reduce the income-tax base but never the social-surcharge base, a distinction that destroys many a spreadsheet. There is no French equivalent of the UK annual exempt amount: the first euro of net gain is taxable, and the sterling-to-euro conversion can itself create or inflate a gain when the pound has risen since purchase.
Social surcharges deserve a paragraph of their own because British pensioners in particular assume that an S1 healthcare certificate or a UK-only income exempts them. Article L. 136-6 of the Social Security Code 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” — French tax residents pay the contribution on net capital gains taken into income tax. Case law confirms that these surcharges, created after older treaties, count as analogous taxes covered by treaty machinery where they sit on income subject to income tax. In the Conseil d’État decision cited above, the court accepted that social charges assessed on a share gain were part of the charge to be relieved under the treaty credit, while insisting that the domestic charge itself stood unless the treaty removed it. Concretely: budget 30 per cent overall on an ordinary listed-share gain, compare the progressive election on a full simulation, and never assume an S1 or a UK personal allowance removes the French social charge on a securities gain — that exemption, where it exists, concerns specific pension and employment income, not gains within Articles 150-0 A to 150-0 F.
II. What Does the France-UK Tax Treaty Change and How Do I Declare and Challenge the Bill?
A. Which Country May Tax My UK Share Gain Under the Treaty, and What Credit Removes Double Tax?
The France–United Kingdom convention signed on 19 June 2008 and in force allocates taxing rights article by article, and for shares the decisive provision is Article 14 (capital gains) as published in the official English text on GOV.UK. Paragraph 1 gives immovable property — land and buildings — to the State where it stands; paragraph 2 gives shares and rights deriving most of their value from such immovable property to that same State; paragraph 3 covers business assets of a permanent establishment; paragraph 4 covers ships and aircraft. Ordinary shares in a trading or industrial company listed in London fall into none of these, and paragraph 5 then provides the residence-only rule: paragraph 5 then lays down the residence-only rule for everything else: such gains are taxable only in the State where the seller is resident (see the official English text of Article 14 of the 2008 convention on GOV.UK) If you are treaty-resident in France when you sell Tesco or Shell shares, France alone may tax; the United Kingdom, as the other State, may not. That is why a French-resident seller normally owes no UK capital gains tax on the disposal and should not ceil the French credit by UK tax that was never properly due. The French tax administration’s own doctrine on the British convention, published in the Bulletin officiel des finances publiques (BOFiP, the administration’s binding published guidance) under BOI-INT-CVB-GBR-10-30, organises the elimination of double taxation on exactly this residence logic, and the treaty article itself is the authority to cite in any reclaim.
Three boundaries qualify that comfort, and each generates files. First, property-rich entities: paragraph 2 allows the State where the buildings stand to tax gains on shares, other than those regularly traded on an approved stock exchange, deriving most of their value from its immovable property, and on interests in partnerships or trusts whose assets consist principally of such property. A holding in an unlisted UK property company, a British limited partnership owning French barns converted to gîtes, or units in a trust wrapped around a Paris flat may therefore be taxable in France even if you were UK resident — or taxable in the United Kingdom if the buildings stand there and you live in France, with a French credit to compute. The Cour de cassation reads such property-rich clauses literally: construing an analogous treaty, it quoted that “les gains provenant de l’aliénation d’actions, parts ou autres droits dans une société, une fiducie ou toute autre institution ou entité, dont l’actif ou les biens sont constitués pour plus de cinquante pour cent de leur valeur” “de biens immobiliers situés dans un Etat contractant ou de droits portant sur de tels biens ne sont imposables que dans cet Etat.” Check what your fund or company actually holds before assuming the residence-only rule: a “UK shares” label on a broker statement can conceal a property-heavy underlying portfolio, and a REIT or property-authorised fund needs separate analysis under the dividends and gains articles.
Second, the six-year tail in paragraph 6: that residence-only rule is expressly preserved alongside a six-year tail: paragraph 6 keeps each State free to tax under its own law a person who is its resident in the year of disposal or was its resident at any time during the previous six fiscal years (see the same official Article 14 text) A person who leaves France for England and sells shares two years later can therefore face a French charge alongside the UK one, with Article 24 deciding which State eliminates. Within Article 24, the treaty distinguishes gains taxable only by reason of paragraph 6 — where the State taxing under the tail must give relief as if the gains arose in the other State — from gains covered by paragraphs 1, 2 or 3, where the other State gives relief. Map your facts onto that paragraph before paying either bill, because the wrong State’s credit computation is the commonest source of unrelieved double tax in leaver cases. Our separate analysis of a French resident selling a United Kingdom house, where immovable property reverses the allocation, shows the mirror image and why shares and houses must never be reasoned about together.
Third, the mechanics of relief on the French side for the cases where both States may tax — property-rich shares, the tail, and gains remitted under the UK remittance basis. The treaty provides a credit (crédit d’impôt) capped at the French tax attributable to the same income: UK tax actually and correctly paid in accordance with the treaty reduces the French bill pound for pound up to the French amount, with any excess neither refunded nor carried forward. Three practical points follow. UK tax paid in breach of the treaty — for example UK tax on an ordinary listed-share gain realised while exclusively French treaty-resident — does not generate a French credit, because the credit only covers tax levied in accordance with the convention; the remedy is a reclaim from HMRC, not a bigger French credit. French social surcharges follow the income-tax fate as analogous taxes where the treaty covers them, as the Conseil d’État accepted in the decision above. And currency matters twice: the gain is computed in euros for France and in sterling for the United Kingdom, so the two taxable bases legitimately differ, and the credit is limited by reference to the French base. Attach the HMRC computation, the self-assessment statement of account and proof of payment, all converted and reconciled, rather than a bare sterling figure the French agent cannot verify.
B. How Do I Declare the Gain on Forms 2074, 2047 and 2042 and Challenge a Wrong Bill?
French filing rests on a simple statutory command with heavy consequences. Article 170 of the Tax Code 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, de ses charges de famille et des autres éléments nécessaires au calcul de l’impôt sur le revenu” — every taxable person must send a detailed return of income, household and every element needed to compute the tax. For a UK share disposal by a French resident, that command materialises as three coordinated forms. The imprimé 2074, whose official filing page and notice are published by the administration on impots.gouv.fr for Form 2074, gains and losses realised, carries the line-by-line computation: designation of each security, dates and prices of acquisition and disposal, costs, corporate actions, prior losses carried forward, and the resulting net gain or carryable loss. The imprimé 2047 (foreign income schedule) reports the foreign-source character and supports any foreign-tax credit claim. The imprimé 2042 and its complémentaire 2042-C receive the totals that actually drive the assessment, including the box for the PFU versus progressive election. File all three consistently: a 2074 showing a gain with no matching 2047/2042 entry, or a 2042 entry with no 2074 detail, is the standard trigger for an automated query.
Build the evidential bundle before you type a single figure. For each disposal line, assemble the acquisition contract note or subscription statement, every corporate-action notice affecting base cost, the disposal contract note, the broker’s annual consolidated statement, the sterling-to-euro conversions with the rates used, the calculation of costs deducted, the history of losses brought forward with copies of the prior 2074s that recorded them, and, where a credit is claimed, the HMRC computation and proof of UK payment with an explicit statement of why that UK tax was due under the treaty article relied upon. Where the shares were inherited, add the UK grant of probate valuation and any French succession filing; where they came by gift, add the acte de donation (notarial deed of gift) and its registered value; where an employer plan is involved, add the plan rules, vesting notices and payslips showing amounts already taxed as salary, so the same pounds are not taxed again as gain. Non-French documents need no sworn translation by default, but an agent who cannot understand a schedule cannot allow a credit: a one-page reconciliation table in French, mapping each broker line to each 2074 line, with dates, sterling amounts, conversion rates and euro results, routinely decides whether the file is accepted or reassessed. Keep everything until all reassessment and litigation periods have expired, and longer where losses are still being carried forward.
Expect three standard challenges from the administration and prepare each answer in advance. The agent may dispute residence and assert that the gain belongs elsewhere, or that the treaty tie-breaker makes you UK resident: answer with the foyer timeline and Article 4 B evidence described in Part I. The agent may reclassify the gain — treating a property-rich share as an ordinary share or vice versa, or treating a distribution as a disposal — which changes the taxing State under Article 14: answer with the company’s accounts, the listing status on an approved exchange, and the treaty paragraph relied upon, quoted. Or the agent may simply recompute the base cost, disallowing undocumented costs or ignoring a brought-forward loss: answer with the contract-note chain and the prior filed 2074s. In each case the administration bears its burden once you have produced coherent documentary proof, but bare assertions in a covering letter carry no weight. The Conseil d’État method quoted above is your shield and your discipline: show first that the domestic charge as recomputed by the agent is wrong on its own terms, then show that the treaty confirms your position — never the reverse.
If the assessment or the reassessment is already issued, French procedure gives you a structured ladder, and deadlines are strict. Begin with a réclamation contentieuse (formal tax claim) to the DGFiP, setting out facts, law and relief sought, with every exhibit indexed; the claim suspends enforced collection only if you apply for a sursis de paiement (stay of payment) with the guarantees the accounting officer requires. If the claim is rejected expressly or by silence after six months, appeal to the tribunal administratif (administrative court) within two months of notification, then, if needed, to the cour administrative d’appel (administrative court of appeal) and ultimately by pourvoi en cassation (final appeal on points of law) to the Conseil d’État. Alongside, correct what can still be corrected: a return filed on time can usually be amended online within the correction window, and a UK overpayment can be reclaimed from HMRC under the treaty while the French credit is recomputed. Never pay a doubly-taxed bill and “sort it out later” without filing the protective claim: payment without a timely claim can become final even where the law was on your side. Diarise every date from the assessment notice itself, serve claims by a provable channel, and keep proof of each sending.
Conclusion
A British resident of France who sells London-listed shares after Brexit lives under a clear but demanding sequence: French domestic law claims the worldwide gain through Articles 4 A and 4 B, computes it through Articles 150-0 A and 150-0 D, charges it at 12.8 per cent plus social surcharges through Article 200 A and Article L. 136-6 unless the progressive election suits the household better, and then yields to the France–United Kingdom treaty, whose Article 14(5) reserves ordinary listed-share gains to the State of residence while paragraphs 2 and 6 preserve defined exceptions for property-rich shares and recent leavers. The courts enforce that order exactly — domestic charge first, treaty second — and they quote the texts strictly, as the Conseil d’État and the Cour de cassation passages above demonstrate. Your file should mirror that discipline: prove residence with a dated timeline, compute the euro gain line by line on Form 2074 with every contract note behind it, coordinate Forms 2047 and 2042 without contradiction, claim only treaty-compliant foreign tax as a capped credit, and challenge any error through a timely formal claim and, if needed, the administrative courts. Prepared that way, an ordinary portfolio sale produces one tax bill in the right State, not two in both.