You are British, you live in France, and your healthcare is covered by an S1 form issued by the United Kingdom. Then your French tax notice arrives, and the social charges on your rental income, your interest or your capital gain read 17.2 per cent. For an S1 holder, that figure is very often wrong. Where France is not the state responsible for your sickness cover, you do not owe the CSG (contribution sociale g\u00e9n\u00e9ralis\u00e9e, the general social contribution) or the CRDS (contribution pour le remboursement de la dette sociale, the social debt repayment contribution) on income from capital. Only the pr\u00e9l\u00e8vement de solidarit\u00e9 (the solidarity levy, a 7.5 per cent tax-like charge that is not a social security contribution) remains due. The French tax administration says so itself on impots.gouv.fr, and the Cour de cassation applies the single-legislation rule strictly. This guide explains which income is covered, how to prove your position with your S1, and how to claim back overpaid charges before the deadline expires.<\/p>\n
An S1 (formerly E106, E109 and E121) is a portable document issued by the state that pays your pension or employs you, certifying that you are insured for healthcare in another state at its expense. When you register a UK-issued S1 with your local CPAM (caisse primaire d’assurance maladie, the local French health insurance fund), the United Kingdom remains the state competent for your sickness cover and reimburses France for your treatment. The official GOV.UK guidance on healthcare for British nationals living in France confirms the route: you obtain the S1 from the United Kingdom and you register it with the CPAM, after which you access French healthcare as an S1 holder rather than as a person insured under the French scheme. Keep that registration certificate safe, because it is the document on which everything else depends. Read the current procedure here: Healthcare for UK nationals living in France – GOV.UK<\/a>.<\/p>\n The legal consequence follows from the coordination rules. Within the European system, and under the social security protocol of the EU-UK Trade and Cooperation Agreement after Brexit, a person is subject to the social security legislation of one state only at any given time. The French Cour de cassation stated the principle in these exact terms: Cour de cassation, deuxi\u00e8me chambre civile, 30 janvier 2025, pourvoi n\u00b0 22-22.464<\/a>, “les personnes auxquelles ce r\u00e8glement est applicable ne sont soumises qu’\u00e0 la l\u00e9gislation d’un seul \u00c9tat membre”. A single state means a single bill: if the United Kingdom is competent for your sickness insurance, France cannot add a second layer of social charges on top. The same judgment recalls that income received in a state other than the competent state must be subjected to contributions in the competent state, citing expressly the Court of Justice judgment De Ruyter of 26 February 2015 (C-623\/13). The De Ruyter case is the foundation of the whole subject: Mr de Ruyter, a Dutch national working in the Netherlands but living in France, was charged French CSG and CRDS on his Dutch income, and the Court of Justice held that levies with a direct and relevant link to social security fall under the single-legislation rule, so France could not charge them to a person already subject to another state’s scheme. Your S1 is the practical proof that you are that person.<\/p>\n French statute law then converts the principle into an express exemption. Article L. 136-6 of the Social Security Code, which creates the CSG on income from capital (revenus du patrimoine: rental income, annuities, investment income, capital gains and similar items), provides in its paragraph I ter: article L. 136-6 du code de la s\u00e9curit\u00e9 sociale<\/a>, “ne sont pas redevables de la contribution les personnes qui, par application des dispositions du r\u00e8glement (CE) n\u00b0 883\/2004 du Parlement europ\u00e9en et du Conseil du 29 avril 2004 sur la coordination des syst\u00e8mes de s\u00e9curit\u00e9 sociale, rel\u00e8vent en mati\u00e8re d’assurance maladie d’une l\u00e9gislation soumise \u00e0 ces dispositions et qui ne sont pas \u00e0 la charge d’un r\u00e9gime obligatoire de s\u00e9curit\u00e9 sociale fran\u00e7ais.” The twin provision for investment products and property gains, article L. 136-7, contains the same exemption and adds the machinery: the paying institution does not withhold the contribution once the holder proves the position, and any undue withholding can be repaid by the payer or reclaimed from the tax administration. Read it here: article L. 136-7 du code de la s\u00e9curit\u00e9 sociale<\/a>, “ne sont pas redevables de la contribution les personnes qui, par application des dispositions du r\u00e8glement (CE) n\u00b0 883\/2004 du Parlement europ\u00e9en et du Conseil du 29 avril 2004 sur la coordination des syst\u00e8mes de s\u00e9curit\u00e9 sociale, rel\u00e8vent en mati\u00e8re d’assurance maladie d’une l\u00e9gislation soumise \u00e0 ces dispositions et qui ne sont pas \u00e0 la charge d’un r\u00e9gime obligatoire de s\u00e9curit\u00e9 sociale fran\u00e7ais.” Two conditions therefore decide your case, and both must be met on the relevant date: you come under another coordinated sickness legislation (your registered S1 proves this), and you are not chargeable to a compulsory French health scheme (no French employment, no PUMA affiliation as a French-insured person alongside the S1). The Cour de cassation gives evidential teeth to such certificates: a certificate issued by the designated institution of the competent state binds the institutions and courts of the state where the work is performed, even where they consider the conditions manifestly unmet, and disputes must go through the inter-institution dialogue procedure. That was said of an E 101 posting certificate, but the logic is the same family: Cour de cassation, deuxi\u00e8me chambre civile, 24 janvier 2019, pourvoi n\u00b0 17-20.191<\/a>, “un certificat E 101 d\u00e9livr\u00e9 par l’institution d\u00e9sign\u00e9e par l’autorit\u00e9 comp\u00e9tente d’un Etat membre, au titre du deuxi\u00e8me texte, lie tant les institutions de s\u00e9curit\u00e9 sociale de l’Etat membre dans lequel le travail est effectu\u00e9 que les juridictions de cet Etat membre”. Do not surrender your S1, do not let it lapse without renewing it, and never accept an argument that a French form alone overrides a British certificate without the formal dialogue between institutions.<\/p>\n One boundary must be stated clearly, because confusing it loses cases. The exemption covers the CSG and CRDS on income from capital and on investment products. It does not exempt you from everything with the word social in it. Employment and replacement income are governed by article L. 136-1, which taxes persons who are both domiciled in France for income tax and chargeable to a compulsory French sickness scheme: article L. 136-1 du code de la s\u00e9curit\u00e9 sociale<\/a>, “Les personnes physiques qui sont \u00e0 la fois consid\u00e9r\u00e9es comme domicili\u00e9es en France pour l’\u00e9tablissement de l’imp\u00f4t sur le revenu et \u00e0 la charge, \u00e0 quelque titre que ce soit, d’un r\u00e9gime obligatoire fran\u00e7ais d’assurance maladie”. If you work in France and pay into the French scheme, your salary follows the French rules regardless of your British passport. Likewise, the cotisation subsidiaire maladie (the PUMA top-up contribution for residents with little or no French professional income) is a different levy under article L. 380-2, aimed at persons covered by the French universal scheme: article L. 160-1 du code de la s\u00e9curit\u00e9 sociale<\/a> defines the PUMA beneficiaries as persons working in France or residing there in a stable and regular way, “Toute personne travaillant ou, lorsqu’elle n’exerce pas d’activit\u00e9 professionnelle, r\u00e9sidant en France de mani\u00e8re stable et r\u00e9guli\u00e8re b\u00e9n\u00e9ficie, en cas de maladie ou de maternit\u00e9, de la prise en charge de ses frais de sant\u00e9”, and article L. 380-2 du code de la s\u00e9curit\u00e9 sociale<\/a> charges the contribution to those persons. An S1 holder registered through the S1 is not a PUMA beneficiary in the relevant sense, which is exactly why the S1 route and the PUMA route must never be mixed in the same file. Recent litigation shows how strictly courts police these borders: the Paris social court had to decide whether a person covered only by private insurance could be charged the PUMA contribution (Tribunal judiciaire de Paris, p\u00f4le social, 25 janvier 2024, RG 22\/02568), and the Nanterre social court dealt in January 2026 with contributions claimed on board members affiliated to another member state’s scheme (Tribunal judiciaire de Nanterre, p\u00f4le social, 7 janvier 2026, RG 23\/01040). The lesson for your file is simple: one status, one proof, one set of rules. If you are an S1 holder, argue as an S1 holder from the first line to the last.<\/p>\n The CSG on income from capital catches almost everything a British resident in France lives on besides a salary: furnished and unfurnished rental income (revenus fonciers and BIC for furnished lets), life annuity payments bought for consideration, dividends and interest, taxable capital gains on shares and on property, and several professional profits taxed as income but not subject to CSG on earnings. Your French tax notice lumps the social charges together, which is why the error hides so well: the notice shows one global rate, currently 17.2 per cent in the standard case (9.2 per cent CSG, 0.5 per cent CRDS and 7.5 per cent solidarity levy), and an S1 holder should in principle pay only the last slice. The administration confirms the arithmetic on its own international pages: persons affiliated to a compulsory social security scheme other than the French one are exempt from CSG and CRDS, and British residents keep that exemption even though the United Kingdom left the European Union on 1 January 2021, with only the 7.5 per cent solidarity levy remaining due (see impots.gouv.fr, non-resident social charges page<\/a>). Service-public.fr states the same outcome in English for residents affiliated to another country’s compulsory scheme: no CSG and no CRDS, only the 7.5 per cent solidarity levy (see service-public.fr, social levies on wealth and investment income (English)<\/a>).<\/p>\n Work through three everyday examples so you can check your own notice. First, rental income. Suppose you let a flat in Lyon and declare 12,000 euros of net rental profit. At the full 17.2 per cent, the social charges come to 2,064 euros; at 7.5 per cent, they come to 900 euros. The difference of 1,164 euros is the refund to claim for that year, and the same calculation repeats for every open year. Readers who let property will find the companion treatment of how France taxes the rent itself, and how the treaty credit works, in our guide to British rental income in France and the treaty credit<\/a>; the present article answers the narrower social-charges question that the companion guide leaves open. Second, interest and dividends. A 5,000-euro interest payment suffers 860 euros of charges at the full rate against 375 euros at 7.5 per cent, a 485-euro difference, and the same logic applies to dividends before any treaty withholding is considered. Third, a property capital gain. On a taxable gain of 80,000 euros, the gap between 17.2 per cent (13,760 euros) and 7.5 per cent (6,000 euros) is 7,760 euros for a single disposal, which is why vendors should check the social-charges line of the notaire’s computation before signing, not after. These are illustrations, not assessments: your notice, your S1 dates and any French affiliation in the same year decide the real figure.<\/p>\nB. Which income the exemption covers, what still costs 7.5 per cent, and how the numbers work<\/h3>\n