You live in France, and you still own a flat in Manchester, a terrace in Leeds or a maisonette in London that you let to tenants. Every month the rent lands in your British bank account, tax already nibbled at source by the letting agent, and every spring the same worry returns: must you declare that rent again in France, will you be taxed twice on the same pounds, and what happens to the French social charges that keep appearing on your tax notice? Since Brexit these questions have become sharper, because British landlords settled in France are now dealt with as residents receiving income from a third country, with full French reporting duties, foreign-account statements and penalties that have nothing to do with the old European routines. This guide explains, step by step, where your British rental income is really taxed, how the Franco-British tax treaty prevents double taxation through a credit rather than an exemption, which social charges survive when you hold an S1 healthcare certificate, which French forms and boxes to use, and how to challenge a tax notice that charges you twice or fines you unfairly. It is written for a British reader: every French term is explained the first time it appears, and every decisive rule is quoted from the statute, the official tax commentary or a court decision you can check yourself.

I. Where Is UK Rental Income Taxed When You Live in France After Brexit?

Two tax authorities look at the same rent: HM Revenue and Customs in the United Kingdom, where the property stands, and the Direction générale des Finances publiques in France, where you live. Understanding which of them taxes first, and how the second one gives relief, is the key to the whole subject. The short answer is that both tax you, but France must then wipe out the double charge with a tax credit. The sections below show why, with the exact texts.

A. Why the United Kingdom taxes first and France taxes again with a credit

French tax residence is what pulls your worldwide income into the French net. Article 4 A of the French Tax Code (Code général des impôts) states: “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: anyone whose tax home (domicile fiscal) is in France pays French income tax (impôt sur le revenu) on all of their income, wherever it comes from. Your Manchester rents are therefore inside the French base from the moment you are French-resident, even though the bricks and the tenants never left England. The residence tests themselves are set by Article 4 B of the same code: “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”. Your family home (foyer) or your main place of stay (lieu du séjour principal) in France is normally enough on its own. Most British settlers meet the first test within months of moving, long before they feel fully installed.

Once you are French-resident, the rents must be classified. French law puts them in the property-income category (revenus fonciers). Article 14 of the Tax Code provides: “Sous réserve des dispositions de l’article 15 , sont compris dans la catégorie des revenus fonciers, lorsqu’ils ne sont pas inclus dans les bénéfices d’une entreprise industrielle, commerciale ou artisanale, d’une exploitation agricole ou d’une profession non commerciale : 1° Les revenus des propriétés bâties, telles que maisons et usines”. A British buy-to-let held privately falls squarely into that category, so the rents join your French taxable income under the ordinary property-income rules, with deductible expenses calculated the French way and supporting invoices kept in your files.

The Franco-British double-tax treaty, signed in London and still fully in force after Brexit, then decides how the two countries share the tax. Its property article follows the international standard: immovable property is taxed where it stands. The French tax administration’s official commentary (Bulletin officiel des finances publiques, BOI-INT-CVB-GBR-10-20) confirms that income from direct use, letting or any other use of property situated in a contracting state is taxable in that state under paragraph 5 of Article 6 of the treaty. For a British flat let to tenants, the taxing state (État de la source) is therefore the United Kingdom, and the commentary adds the decisive priority rule that the source state’s right to tax takes precedence over the other state’s right. In practice HMRC taxes the rents under British rules first, and France, as your residence state, taxes them second but must eliminate the resulting double taxation.

On the British side, that first taxation usually happens before the money even reaches you. HMRC runs the Non-Resident Landlords Scheme, which the official GOV.UK guidance describes it as the scheme taxing the UK rental income of landlords whose usual home is outside the United Kingdom. Under it, letting agents must withhold tax from the rent and pay it to HMRC, unless HMRC has agreed in writing that the landlord may be paid gross with no tax deducted. Many French-resident landlords therefore receive their rents either net of British withholding or gross with HMRC’s written approval, and in both cases they must still file a British Self Assessment return for the property income and keep the British tax assessments. Those assessments are gold dust: the French tax office will ask for them when it checks your treaty credit, so keep every HMRC calculation, every letting-agent statement and every proof of British tax paid.

The French side of the mechanism is a credit, not an exemption, and this is where most mistakes begin. The impots.gouv.fr guidance on foreign-source income explains the paperwork chain: start with annexe 2047, which details income received abroad including property income, carry the amounts onto the main return, and then claim the treaty relief through the tax-credit boxes of complementary return 2042-C. The credit equals the British tax so that the same pound of rent is not taxed twice in economic terms, but the rent itself stays visible in your French taxable income. That visibility matters for your effective tax rate, your social charges and your household quotient (quotient familial), which is why declaring the gross rent and then claiming the credit box is never equivalent to omitting the rent altogether.

A common and costly misunderstanding is to read the treaty as a permission to ignore France entirely. It is the opposite: the treaty shares taxing rights, and France keeps hers. Two recent courtroom warnings illustrate the point for French property structures held through companies, and the logic carries straight over to individuals with cross-border rents. In a 2 April 2025 ruling (pourvoi n° K 23-14.568), taxpayers argued that shares in French property companies should escape French wealth tax because “la convention fiscale entre la France et le Grand-duché de Luxembourg du 1er avril 1958 prévoyant, selon eux, la taxation de ces éléments de fortune au Luxembourg”. The Cour de cassation answered: “REJETTE le pourvoi”. A year later, before the Paris judicial court (tribunal judiciaire de Paris, judgment of 5 May 2026, RG 24/13163), a Dutch-resident couple holding shares in French property companies asked the court to and asked the court to discharge the tax and penalties on the ground that the Franco-Dutch treaty reserved taxation to the Netherlands; the court dismissed the couple’s claims in full. Treaties allocate tax, they do not make income disappear. Declare the British rents in France, claim the credit lines, and attach the British proof: that is the only safe reading of the treaty.

One practical detail deserves its own paragraph: currency. British rents arrive in sterling and French returns are filed in euros, so convert each year’s rents with a consistent, documented method and keep the calculation with your letting records. If the tax office queries your figures, a clean conversion schedule next to the HMRC assessments and the bank statements closes the discussion fast, while a bare euro total with no workings invites a reassessment. Keep also the tenancy agreements, the management fees and the repair invoices, because deductible expenses are examined under French property-income rules even though the house stands in Britain.

B. Which French social charges still apply, and when your S1 certificate exempts you

Income tax is only half of the French bill. On top of it, France levies social contributions (prélèvements sociaux) on investment and property income, and British landlords are often shocked to find them on rents that already bore British tax and French income tax with a credit. The charging provision is Article L. 136-6 of the Social Security Code (Code de la sécurité sociale): “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”, and the same article lists “a) Des revenus fonciers” among the caught income. Your British rents, once classified as revenus fonciers for income tax, therefore enter the base of the French social contributions on capital income (contribution sociale sur les revenus du patrimoine), currently made of the CSG (contribution sociale généralisée) and the CRDS (contribution au remboursement de la dette sociale) elements. Unlike income tax, these contributions are generally not covered by the treaty’s tax-credit mechanism, so they can feel like a second layer of double taxation even when the income-tax credit works perfectly.

There is, however, a targeted exemption for people who are covered for healthcare (assurance maladie) in another state, and it matters enormously to British pensioners and early retirees holding an S1 form. An S1 (formerly E106/E121) is the certificate by which the United Kingdom, as the state paying your state pension or covering you under the coordination rules, takes charge of your French healthcare costs, with the French health fund (CPAM, caisse primaire d’assurance maladie) registering you on that basis. Article L. 136-6, I ter, of the Social Security Code provides: “Par dérogation aux I et I bis, ne sont pas redevables de la contribution les personnes qui, par application des dispositions du règlement (CE) n° 883/2004 du Parlement européen et du Conseil du 29 avril 2004 sur la coordination des systèmes de sécurité sociale, relèvent en matière d’assurance maladie d’une législation soumise à ces dispositions et qui ne sont pas à la charge d’un régime obligatoire de sécurité sociale français.” In ordinary language: if European coordination puts your healthcare under another state’s legislation and you are not borne by a French compulsory health scheme, you do not owe the CSG/CRDS element on your capital income, including your British rents. For British S1 holders resident in France, that exemption is the difference between roughly seventeen percentage points of charges and a far lighter bill, so it is worth organising your status deliberately rather than discovering it on a tax notice.

The Cour de cassation has just restated the principle behind that exemption in the strongest terms. On 25 September 2025 (Second Civil Chamber, pourvoi n° F 22-24.634, ECLI:FR:CCASS:2025:C200872), the court recalled that the European 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 (CJUE, arrêt du 26 février 2015, De Ruyter, C-623-13, point 35)”. One person, one social-security legislation: that is the unicity rule (principe d’unicité), inherited from the famous De Ruyter judgment of the Court of Justice of the European Union. If your S1 genuinely places your healthcare under British cover and you are not simultaneously carried by a French compulsory scheme, charging you French CSG and CRDS on your British rents contradicts that rule, and the I ter exemption is the domestic provision that gives effect to it.

One charge nevertheless survives the S1 in most cases: the solidarity levy (prélèvement de solidarité). Article 235 ter of the Tax Code creates a solidarity levy on the capital income caught by Article L. 136-6 of the Social Security Code, and it fixes the burden: “Le taux des prélèvements de solidarité mentionnés au I est fixé à 7,5 %.” Because that levy is legally classified outside the CSG/CRDS contributions caught by the exemption, S1 holders normally still pay 7.5% on the net British rents. Budget for it from the start: it removes the sting of the full charge without removing everything, and forgetting it produces the classic bewildered phone call in November when the assessment (avis d’imposition) arrives.

Three practical consequences follow for the post-Brexit British landlord. First, register your S1 with the CPAM promptly after arrival and keep the registration certificate alongside the S1 itself; without proof of cover under the other state’s legislation, the tax office will simply apply the full charges and leave you to claim later. Second, check the personal scope of the EU–UK Withdrawal Agreement as it applies to you, because European coordination now reaches British citizens through that agreement rather than through membership, and borderline cases such as late movers, returning pensioners and people splitting work between the two countries need individual analysis. Third, if full social charges were wrongly applied for years when your S1 was valid, quantify the CSG/CRDS element separately from the 7.5% solidarity levy before claiming anything: asking for the whole charge back when part of it was lawfully due weakens an otherwise strong file. A claim that says precisely which contribution, for which year, under which S1, with the CPAM certificate attached, is answered faster and more favourably than a blanket demand for everything.

II. How Do You Declare UK Rents in France, Pay on Time and Challenge Double Tax?

Knowing the rules is one thing; getting the paperwork right each spring is another. French reporting of British rents runs through a fixed chain of forms, and every link in that chain is checked automatically: the foreign-income annexe, the main return, the complementary return with the treaty credit, and the separate statement of your British bank accounts. Miss one link and the system either taxes you twice or fines you. Work through the chain in order and keep the proofs, and the same system works in your favour when you need to challenge a mistake.

A. Which forms, boxes and statements: 2047, 2042, 2042-C and the foreign bank account declaration

Start with the annexe for foreign income (annexe 2047, déclaration des revenus encaissés à l’étranger). The official impots.gouv.fr guidance describes it as the annexe detailing income received abroad, including property income, which confirms in passing that foreign property rents belong on that annexe. Enter the gross British rents there, property by property, with the deductible expenses computed under French property-income rules, and identify the country as the United Kingdom with the British tax paid shown alongside. The guidance then gives the next step: after completing annexe 2047, carry the amounts onto the boxes of main return 2042. The 2042 is the main personal return (déclaration d’ensemble des revenus) that every French tax resident files each spring; your British rents must appear in it even though they were taxed in Britain, because residence taxation under Article 4 A is worldwide and the treaty gives a credit rather than an invisibility cloak.

The credit itself lives on the complementary return 2042-C (déclaration complémentaire), in the dedicated treaty-credit boxes. The impots.gouv.fr guidance instructs that the tax credit goes on lines 8VL, 8VM, 8WM or 8UM of complementary return 2042-C. Choose the line that matches your situation, enter the British tax that corresponds to the declared rents, and attach or hold ready the HMRC assessments proving it. Two details decide whether the credit survives inspection. First, the credit can only neutralise the French tax on those rents; it cannot create a refund beyond it, so compute it rent-stream by rent-stream rather than as a global lump. Second, the British proof must match the declared amounts: if the HMRC assessment shows a different net because of British-only allowances, reconcile the figures in a short note rather than leaving the inspector to guess. A one-page reconciliation schedule, in euros, stapled to the British assessment, is the cheapest insurance a cross-border landlord can buy.

Alongside the income returns, declare your British bank and investment accounts on the foreign-account statement (formulaire 3916, déclaration des comptes ouverts, détenus, utilisés ou clos à l’étranger). The duty comes from Article 1649 A of the Tax Code: “Les personnes physiques, les associations, les sociétés n’ayant pas la forme commerciale, domiciliées ou établies en France, sont tenues de déclarer, en même temps que leur déclaration de revenus ou de résultats, les références des comptes ouverts, détenus, utilisés ou clos à l’étranger.” Every current account that receives the rents, every savings account where the balance waits, every joint account with a British-resident spouse: each must be listed each year, even if the balance barely moves. Since Brexit the United Kingdom is a third country for this purpose, so the administration watches these statements closely, and the rent trail from a British letting agent to an undeclared British account is exactly the pattern its software is built to detect.

The fines for forgetting are deliberately painful. Article 1736, IV, of the Tax Code provides: “Les infractions aux dispositions du deuxième alinéa de l’article 1649 A et de l’article 1649 A bis sont passibles d’une amende de 1 500 € par compte ou avance non déclaré.” With two undeclared accounts over three years, the arithmetic becomes frightening, and that is before the income-tax consequences of the rents themselves. Late or missing income returns attract their own scale under Article 1728: “Le défaut de production dans les délais prescrits d’une déclaration ou d’un acte comportant l’indication d’éléments à retenir pour l’assiette ou la liquidation de l’impôt entraîne l’application, sur le montant des droits mis à la charge du contribuable ou résultant de la déclaration ou de l’acte déposé tardivement, d’une majoration de : a. 10 % en l’absence de mise en demeure ou en cas de dépôt de la déclaration ou de l’acte dans les trente jours suivant la réception d’une mise en demeure”. The rate climbs to 40% after an ignored formal demand (mise en demeure) and 80% for hidden activity, so a forgotten British flat can quickly cost multiples of the original tax. Declare everything, on time, every year: with cross-border rents there is no efficient shortcut.

File within the deadline shown in your online personal space (espace particulier) on impots.gouv.fr, and keep the filing receipts. If you use a letting agent, ask each spring for an annual statement in a format you can file, and reconcile it immediately with your bank credits while the season is still fresh. If you manage the property yourself, keep the tenancy agreement, the rent receipts, the repair invoices and the travel records for inspections, because French deductible expenses are proved the French way even for a house in Yorkshire. And if your situation changes mid-year, through a sale, a move back to Britain or the death of a co-owner, take advice before the next return rather than improvising boxes you have never used: transitional years generate most of the reassessments this practice sees.

B. How to fix mistakes, claim your treaty credit and appeal fines and double charges

When the assessment arrives, read it before paying it in a hurry. Check that the gross rents match your 2047, that the treaty credit in the 8VL to 8UM lines was actually granted, that the British tax taken into account equals your HMRC assessments, and that the social charges show the S1 exemption if your certificate was registered. The most frequent errors this practice encounters are a missing credit because the complementary return was not filed, a credit capped wrongly because the British proof was not attached, full CSG and CRDS charged despite a valid registered S1, and the 1,500-euro account fines applied to accounts that were in fact declared under a slightly different reference. Each of these has a remedy, but each remedy runs on rails with time limits printed on the notice, so diarise them the day the notice lands.

If you spot your own omission before the administration does, correct it spontaneously. Article 1758 A of the Tax Code charges “une majoration égale à 10 % des droits mis à la charge du contribuable” for late, missing or understated returns, but it then provides a valuable way out: “Cette majoration n’est pas applicable : a) Lorsque le contribuable a corrigé sa déclaration spontanément ou dans un délai de trente jours à la suite d’une demande de l’administration”. A voluntary correction, filed through your online space with the missing 2047, the missing 2042-C credit lines or the forgotten 3916 statement, can therefore wipe out the 10% surcharge entirely. Add the British proofs and a short letter explaining the error in plain terms; inspectors settle honest, documented corrections far more readily than they settle silence followed by argument. Interest for late payment (intérêt de retard) may still run, because Article 1727 states: “Toute créance de nature fiscale, dont l’établissement ou le recouvrement incombe aux administrations fiscales, qui n’a pas été acquittée dans le délai légal donne lieu au versement d’un intérêt de retard.” Interest compensates the Treasury for time, while the surcharge punishes the fault: correcting early removes the punishment even when a modest interest remains.

If instead the error is the administration’s, use the formal claim procedure (réclamation contentieuse). Article L. 190 of the Tax Procedure Book (Livre des procédures fiscales) defines its scope: “Les réclamations relatives aux impôts, contributions, droits, taxes, redevances, soultes et pénalités de toute nature, établis ou recouvrés par les agents de l’administration, relèvent de la juridiction contentieuse lorsqu’elles tendent à obtenir 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.” A denied treaty credit, a doubly counted rent, full social charges despite a registered S1, or an account fine for an account that was declared: all of these are textbook contentious claims seeking either correction of the base or the benefit of a statutory right. File the claim through your online messaging or by recorded letter to the service shown on the notice, within the time limit printed on it, and structure it like a mini-brief: the year, the tax, the amount disputed, the rule relied upon quoted exactly, the evidence attached in order. Join the HMRC assessment with a certified-style translation of the key lines if the figures need explanation, the CPAM registration certificate and the S1 for social-charge disputes, and the 3916 receipts for account-fine disputes.

For social-charge disputes specifically, build the file around the two texts quoted in this guide: the I ter exemption of Article L. 136-6, which removes the CSG/CRDS element for persons covered for healthcare under another coordinated legislation and not borne by a French compulsory scheme, and the unicity principle restated by the Cour de cassation on 25 September 2025, under which a person covered by one member state’s social-security legislation must not contribute to another member state’s scheme. Ask for discharge of the CSG and CRDS elements year by year, accept that the 7.5% solidarity levy stands, and show the calculation so the inspector can grant it without further correspondence. If the claim is rejected expressly or by silence, the dispute moves to the courts, where the same two texts, plus your S1 history and CPAM certificates, form the core of the case. Keep every envelope, every online receipt and every medical-registration document: cross-border social-security cases are won on paper trails, not on rhetoric.

Finally, never let a disputed assessment drift. A claim does not automatically suspend collection, so ask expressly for a suspension of payment (sursis de paiement) with the guarantees the book requires if the sums are significant, and continue to file correctly for later years while the dispute runs: nothing weakens a 2023 claim like a defective 2024 return filed in the middle of it. If penalties at 40% or 80% are on the table, take advice before writing anything, because statements made to explain a delay can be requalified as admissions about its cause. Handled this way, most British-rent files settle: the credit is granted once proved, the S1 exemption is applied once documented, and the account fines fall away once the statements are regularised.

Conclusion

British rental income in French hands follows a clear three-step logic that Brexit left intact: the United Kingdom taxes the rents first because the property stands there, France taxes them second because you live here, and the treaty then neutralises the double income-tax charge through a credit claimed on the 2042-C rather than through any exemption. Around that core, two disciplines decide everything: declare the full chain every spring, with the 2047 annexe, the 2042 main return, the treaty-credit boxes and the 3916 account statements, and organise your S1 healthcare cover so the CSG and CRDS elements of the social charges fall away under the I ter exemption, leaving only the 7.5% solidarity levy. The statutes reward the organised landlord with credits, exemptions and spontaneous-correction relief, and they punish forgetfulness with 10% to 80% surcharges, late-payment interest and 1,500 euros per undeclared account. Keep the HMRC assessments, the letting statements, the S1 and the CPAM certificate in one file, reconcile sterling into euros openly, and challenge errors quickly through reasoned contentious claims. Your British bricks can then fund your French life without funding both Treasuries twice.

Need a quick opinion on your case

Telephone consultation within 48 hours with a solicitor from the firm, to review your British rents, your treaty credit and your S1 position before you file or appeal. Call +33 6 46 60 58 22 or write via our contact page with your latest French tax notice and your HMRC assessment attached.