You bought the stone house in the Dordogne, or the two-bedroom flat in Paris, years before Brexit, and since the pandemic the arithmetic has looked tempting: a few summer weeks on Airbnb or Booking.com would cover the taxe foncière (French local property tax), the insurance and the flights back. Then two letters arrive in the same month. The mairie (town hall) asks for your furnished-tourism registration number and warns that your file may be passed to the change-of-use unit. The French tax office sends an assessment on rent you assumed HMRC had already dealt with. Both letters look routine. Neither is. Since Brexit you let French property as a third-country owner: the European tolerance that once smoothed over missing paperwork is gone, the town halls of the tourist zones run active detection units, and the French and British tax computers now exchange your rental data automatically. The good news is that the system is fully navigable once you understand its two halves. The first half is municipal: register the accommodation, display the number, collect the tourist tax, and secure the change-of-use authorisation where your commune requires one. The second half is fiscal: France taxes the rent first under the bilateral treaty, Britain taxes it second with relief, and each bill can be challenged on paper if you keep the right proofs. This guide walks through both halves in that order, with the exact texts the mairie and the tax office will throw at you, the two recent Court of Cassation rulings that reset the case law in 2024 and September 2026, and the challenge routes that actually work from across the Channel.
I. Before the First Guest Arrives: the Two Municipal Permissions Your Mairie Can Fine You for Missing
A. How Do You Register Your Holiday Let and Get the Declaration Number Guests and Platforms Must See?
Every British owner starts in the same place, whether the property is a farmhouse near Sarlat or a studio in the Marais: before the first paying guest crosses the threshold, the accommodation must be declared to the commune as a meublé de tourisme (furnished tourist accommodation). These are defined in law as “des villas, appartements ou studios meublés, à l’usage exclusif du locataire, offerts à la location à une clientèle de passage qui n’y élit pas domicile et qui y effectue un séjour caractérisé par une location à la journée, à la semaine ou au mois”, which is to say furnished villas, flats or studios let exclusively to short-stay guests who do not live there, by the day, week or month. That definition, in Article L324-1-1 of the Tourism Code, is the gateway to everything else: if your letting matches it, the declaration duty applies to you, British passport or not, resident in France or still living in Kent.
The declaration itself is now a national online formality. The same article requires anyone offering a furnished tourist letting to declare it personally in advance through a national online teleservice, stating in particular whether the property counts as the owner’s main home. Once the file is complete, the teleservice immediately returns an electronic receipt carrying a declaration number. That number is the backbone of the whole control system. It must appear on every advert, the platforms transmit it to the communes, and the mairie cross-checks it against its register. A British owner who lets through an agency is not exempt: the duty lies on the person offering the letting, and an agent’s advert without your number exposes you, not the agent.
Two companions come with the number. The first is classification (classement), the familiar star rating from one to five, granted after an inspection visit. It is voluntary, but the official service-public.fr guide to turning a second home into holiday accommodation explains that communes which levy a tourist tax charge unclassified properties at a higher rate, so most British owners in the tourist departments classify quickly and the inspection pays for itself within a season. The second companion is the taxe de séjour (tourist tax), which Article L2333-26 of the General Local Authorities Code allows communes to create, since “une taxe de séjour ou une taxe de séjour forfaitaire peut être instituée par délibération prise par le conseil municipal avant le 1er juillet de l’année pour être applicable à compter de l’année suivante”. In practice the guest pays it, you collect it on top of the rent, and where you let through a platform the platform collects it in real time and passes it to the commune. The rates vary street by street, because each council votes its own scale before 1 July for the following year, so check the commune’s current scale every spring rather than copying last year’s figure from a forum. The detailed scales sit on the official service-public.fr tourist-tax page. Keep the collection proofs with the booking records: in a later dispute they show a professional, declared operation, which is exactly the image you want to present.
What the French generalist websites add, and where this guide goes further for British readers: the PAP property portal’s Paris guide organises its advice around the capital’s authorisation and compensation machinery, and the PAP Vacances guide walks through the registration number and the change-of-use forms for a French-resident audience. Neither addresses the British position: a non-resident owner who must run the whole procedure by correspondence, appoint a representative for mairie inspections, keep sterling-denominated proofs the tax office will accept, and defend a file from London when the registered letter arrives in August. That cross-Channel practicality, plus the treaty tax treatment below, is what the French guides leave out and what follows now.
B. When Does Short-Term Letting Become a Change of Use That Needs Prior Authorisation?
The registration number is only the first lock on the door. In the communes the Government lists for this regime, principally the large cities, the Paris region and the tense tourist zones, regularly letting a dwelling to short-stay guests legally transforms its use, and that transformation needs the council’s prior permission. Article L631-7 of the Construction and Housing Code states that “le changement d’usage des locaux à usage d’habitation peut être soumis, sur décision de l’organe délibérant, à autorisation préalable”, so the change of use of residential premises may be subjected by council decision to prior authorisation. Three consequences follow for a British second-home owner. First, the rule catches second homes hardest: a Paris pied-à-terre or a Biarritz apartment that you occupy three weeks a year and let for twenty is precisely the profile the detection units look for. Second, the authorisation is local and discretionary within its framework: Paris demands an offset known as compensation (turning other floor space back into housing), other cities run lighter schemes, and some communes simply refuse in saturated streets, with reasons they must state. Third, the price of skipping the step is the heaviest civil fine in French housing law. Article L651-2 of the same code provides that “Toute personne qui enfreint les dispositions des articles L. 631-7 ou L. 631-7-1 A ou qui ne se conforme pas aux conditions ou obligations imposées en application des mêmes articles L. 631-7 et L. 631-7-1 A est condamnée à une amende civile dont le montant ne peut excéder 100 000 € par local irrégulièrement transformé”: up to 100,000 euros per unlawfully converted unit, ordered by the president of the judicial court on application by the commune, plus an order to restore the dwelling to residential use, backed in practice by a daily penalty the official guidance describes as running per day and per square metre until compliance.
Two Court of Cassation rulings, two years apart, have now nailed the definition shut, and British owners should read them as the end of the two most common defences. On 27 June 2024 the Third Civil Chamber quashed a Bordeaux appeal decision that had spared an owner letting a house repeatedly to holidaymakers under a Gîtes de France label. The Court answered, word for word: “Le fait de louer un local meublé destiné à l’habitation de manière répétée pour de courtes durées à une clientèle de passage qui n’y élit pas domicile constitue un changement d’usage au sens de ce texte.” Repeated short lets to passing guests who do not live there are a change of use, full stop. And the tourist classification changes nothing: the Court held that the quality label was independent of, and no substitute for, the council’s authorisation, a point any British owner relying on a star rating or an agency’s reassurance should memorise. The full decision is published as Cass. 3rd civ., 27 June 2024, No 23-13.131, where the Court added that “toute personne, qui enfreint les dispositions de l’article L. 631-7 ou qui ne se conforme pas aux conditions ou obligations imposées en application de cet article, est condamnée à une amende civile”.
On 3 September 2026 the same chamber confirmed the line with even fresher authority in Cass. 3rd civ., 3 September 2026, No 25-16.157, quashing an Aix-en-Provence decision that had excused a landlord on the ground that her seasonal letting, without hotel services, was merely civil in nature. The Court restated the test: “Un local est réputé à usage d’habitation au sens de ce texte s’il était affecté à cet usage au 1er janvier 1970”, so any unit used as housing on 1 January 1970 counts as residential, which covers nearly every British-owned character property. It then repeated that repeated short lets to passing guests are a change of use, and it swept aside the appeal court’s reasoning as legally irrelevant. One technical note matters for files spanning several years: the September 2026 ruling applied the wording predating the Act of 19 November 2024, under which the civil fine “ne peut excéder 50 000 euros par local irrégulièrement transformé”, whereas the current text sets the ceiling at 100,000 euros per unit. Owners whose letting history straddles the reform should therefore check which ceiling the commune’s summons invokes, because the applicable version follows the date of the facts, and a summons citing the wrong ceiling is a point to raise.
Two further traps deserve a paragraph each. The first is the co-ownership rules (règlement de copropriété): the September 2026 owner argued her building rules allowed lettings, and the Court treated that as irrelevant to the public-law authorisation. A clause permitting furnished lets protects you against your neighbours, never against the mairie. Read both documents before buying or before starting to let, and if the building rules ban short lets outright, no council authorisation will save you from a neighbour’s action. The second is the outright refusal: where the council rejects your authorisation request, challenge the refusal within two months before the tribunal administratif (administrative court), with a recours gracieux (informal appeal to the mayor) in parallel to keep the dialogue open. Where you are already summoned for the fine, the case runs before the judicial court on the commune’s application, and the defences that still work are factual and dated: prove the 1970 use was not residential, prove the lets were neither repeated nor short, or prove a valid authorisation covered the period. A missed registered letter put down to living in London is not a defence, which is why every British owner letting in a regulated commune should hold a French postal address or a mandated representative and open every registered letter within days.
II. Who Taxes the Rent: How Do France and Britain Split the Money Without Taxing It Twice?
A. How Is Your French Holiday-Let Profit Taxed in France, and Which Regime Fits a British Owner?
Furnished letting is a commercial activity in French tax law even when you own a single studio. Article 35 of the General Tax Code lists among industrial and commercial profits the gains of “Personnes qui donnent en location directe ou indirecte des locaux d’habitation meublés”, persons letting furnished dwellings directly or indirectly. The label matters enormously: your rent is taxed as BIC (bénéfices industriels et commerciaux, industrial and commercial profits), not as revenus fonciers (unfurnished rental income), with its own thresholds, allowances, forms and social-charge treatment. A British owner who declares the rent on the wrong schedule, or who omits it on the assumption that a UK Self Assessment return covers France, starts every later dispute from a false declaration, and the treaty relief described below only works on income France can see.
For most British second-home owners the entry regime is the micro-BIC, a flat-allowance system that suits modest, distant management. Article 50-0 of the General Tax Code now provides a dedicated threshold: “15 000 € s’il s’agit d’entreprises dont l’activité principale est de louer directement ou indirectement des meublés de tourisme”, so up to 15,000 euros of annual turnover for tourist-furnished letting, with a taxable result after “un abattement de 30 % pour le chiffre d’affaires provenant d’activités de la catégorie mentionnée au 1° bis”, a 30 percent flat deduction. Concretely, 12,000 euros of gross summer rent leaves 8,400 euros taxable before the rate applies, with a minimum allowance of 305 euros. That 15,000-euro ceiling is far lower than the general micro thresholds, it was cut by the 2024 reform, and it is the figure that catches British owners who scaled up from occasional lets to a full season without changing regime: cross it and you fall into the actual-earnings (régime réel) system, where you deduct genuine costs, agency commission, insurance, repairs, interest and depreciation, but where bookkeeping and usually an accountant become compulsory. Neither choice is automatically better. Micro suits the Dordogne farmhouse netting 9,000 euros a summer with few costs; the actual-earnings regime suits the Paris flat with a mortgage, heavy charges de copropriété (building service charges) and a renovation programme. Run both calculations before the second season, because the option, once taken, binds you, and a London accountant unfamiliar with BIC depreciation will rarely optimise it.
Residence then sets the rate. If you live in France, the profit joins your worldwide income under the progressive scale plus social charges. Article L136-6 of the Social Security Code opens with the principle: “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”, so French-domiciled individuals pay social contributions on the net amount used for income tax. If you still live in Britain and let a French house, France taxes the French-source rent but through a floor mechanism: Article 197 A of the General Tax Code provides that for non-residents “l’impôt ne peut, en ce cas, être inférieur à un montant calculé en appliquant un taux de 20 % à la fraction du revenu net imposable inférieure ou égale à la limite supérieure de la deuxième tranche du barème de l’impôt sur le revenu et un taux de 30 % à la fraction supérieure à cette limite”, a minimum levy of 20 percent then 30 percent, unless you show your overall French rate on worldwide income would be lower, in which case that lower rate applies. Non-resident British owners should therefore always test the worldwide-rate option with the actual figures rather than accepting the 20 percent floor by default, and keep every proof of worldwide income the office will ask for.
Social charges for owners straddling the Channel turn on a single European principle that survived Brexit in reshaped form. The Court of Cassation recalled it on 25 September 2025 in Cass. 2nd civ., 25 September 2025, No 22-20.036: the coordination 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 Etat membre, en sorte que celle-ci, affiliée à un régime de sécurité sociale d’un Etat membre, ne doit pas contribuer au régime de sécurité sociale d’un autre Etat membre (CJUE, arrêt du 26 février 2015, De Ruyter, C-623-13, point 35)”. A person affiliated in one state must not pay into another’s scheme. For a British owner today the operative instrument is the social-security protocol attached to the France-UK Trade and Cooperation Agreement rather than the EU regulation itself, but the reflex is identical: identify where you are affiliated, hold the certificate that proves it, and never pay French social charges by default on top of British contributions without checking which legislation covers you. British retirees on a French pension-side affiliation, frontier workers, and seconded staff each sit in a different box, and the box decides the bill.
B. What Must You Still Declare to HMRC, and How Do You Challenge a Wrong Bill on Either Side?
The treaty rule that governs your rent is one sentence long, and it decides everything. Article 6, paragraph 1 of the France-UK double tax convention of 19 June 2008, in the version amended by the multilateral instrument and published on impots.gouv.fr, gives the state where the property sits the first right to tax its rental income, so income from French immovable property is taxable in France. Your Dordogne farmhouse and your Paris studio are French immovable property, so France taxes the rent first, whether you live in London, Leeds or Lyon. Britain then taxes the same rent second as part of your worldwide income, but it must relieve the French tax under the treaty’s elimination article, in practice by crediting the French tax against the UK bill. The order is fixed and non-negotiable: declare in France first, compute the French assessment, then report to HMRC with the French figures. Owners who reverse the order, pay HMRC and then ask France for exemption, wait months for a mechanism that was never designed to run backwards. If you also need to keep your British travel within the post-Brexit limits while managing the property, our companion guide on the 90/180-day rule for British second-home owners sets out how visits, refusals of entry and removal orders work.
On the British side the compliance step is straightforward and frequently skipped. GOV.UK’s foreign-income guidance requires UK residents to report overseas rental income through a Self Assessment return, and its rental-income pages remind landlords living abroad that British letting agents deduct basic-rate tax unless the non-resident landlord scheme is used, a different mechanism that concerns your English buy-to-let, not the French house, but one HMRC officers regularly confuse in correspondence. Report the gross French rent in sterling, claim the credit for the French tax shown on the French assessment, and attach the French notice with a translation of the key lines. Keep the exchange-rate source consistent across years, because HMRC enquiries into French lets almost always start with a currency query, and a file that converts every receipt at a documented Banque de France rate closes that line in one letter. If HMRC opens an enquiry or issues a closure notice you consider wrong, the UK challenge ladder runs from internal review to the First-tier Tribunal, and the French assessment plus the treaty article are your core exhibits there too.
On the French side, challenge discipline decides outcomes far more than rhetoric. Start before the assessment exists: declare the rent on the correct BIC schedule of the 2042 family (the 2042-C PRO professional-income supplement), in euros, with the micro allowance or the actual-earnings accounts clearly identified, and keep every booking statement, platform payout report, agency invoice and works bill for at least the limitation period. When a reassessment proposal (proposition de rectification) arrives, answer within the stated deadline, head by head, invoking the treaty article for the allocation point, the correct code article for the regime point, and the worldwide-rate option of Article 197 A where the minimum levy was applied without examining your global income. A large share of British-owner reassessments settle at this adversarial stage, because they originate in a computer that never saw the BIC schedule or converted sterling at the wrong rate.
Where the assessment is already issued, move to the formal claim. The réclamation contentieuse (contentious tax claim) goes to the tax director with the avis d’imposition (assessment notice) attached, each disputed head listed, the legal grounds stated and discharge or reduction requested, within the strict claim deadlines that run from the notice. A parallel visit to the departmental conciliateur fiscal (tax conciliator) can unblock files where the figures are agreed but the treaty credit was misapplied. If the administration rejects the claim expressly or by silence, appeal lies to the tribunal administratif (administrative court). For owners in Paris and Île-de-France, check the appeal address printed on the rejection letter rather than guessing, because allocation between the Paris and Montreuil courts varies by tax. Throughout, the winning bundle is the same: the complete return with its BIC schedule, every British voucher, the treaty pages for the disputed category, the dated reply to the proposal, the assessment notice and the claim receipt. Courts decide on papers, and a complete, ordered, translated bundle beats an indignant letter every time, nowhere more so than in a file the judge reads as a distant owner who nevertheless declared everything.
Conclusion
Letting a French second home to tourists after Brexit is a two-key system, and British owners fail only when they turn one key and ignore the other. Turn the municipal key first: declare the meublé de tourisme on the national teleservice, display the number, classify where the commune’s tourist-tax scale rewards it, collect the taxe de séjour from every guest, and secure the change-of-use authorisation before the season starts wherever the council requires one, remembering that repeated short lets are a change of use and that neither a star rating nor the building rules replace the council’s permission. Turn the fiscal key second: declare the profit in France as BIC under micro or actual earnings, test the worldwide-rate option before accepting the non-resident floor, prove your social-security affiliation instead of paying twice, and report to HMRC with the French assessment in hand so the treaty credit lands where it should. The September 2026 Court of Cassation ruling shows the direction of travel: councils are winning these cases, fines now run to 100,000 euros per unit, and nostalgia for the pre-Brexit tolerance is not a legal argument. Method is. Run the procedure in the order this guide gives, keep every number and every notice, and challenge each refusal or bill on its own deadline with the text that governs it.
Need a quick opinion on your case
Facing a mairie letter about your registration number, a refused change-of-use authorisation, a summons for the civil fine, or a French assessment on your holiday-let rent that ignores the treaty. Our lawyers review your declaration file, your authorisation position, your BIC return and your assessment notices, then organise the regularisation or the challenge with you. Telephone consultation: 80 EUR incl. VAT, with a lawyer of the firm within 48 hours. Call +33 6 46 60 58 22 or write through our contact page. We receive clients in Paris and across Île-de-France, and we act for British owners throughout France.