You bought a stone house in the Dordogne, the Luberon or the Pays Basque before or after Brexit, and now you want the two improvements every British owner dreams of: a proper swimming pool for the August heat and a kitchen extension so the whole family can eat inside when the evening turns cool. In England you would check permitted development rights, perhaps call the council, and start digging. In France the logic is reversed: almost every visible change to your house or garden needs a prior written permission from the mairie, the mayor’s office, and building first and asking later can end in a criminal fine, a court order to demolish at your expense, and a bill that no insurer will pay. Since Brexit changed nothing in French planning law but changed your administrative position, British owners face the same permits as French neighbours while navigating the forms, the deadlines and the appeals in a second language. This guide explains, for a British second-home owner or new resident, which permission your pool needs, which permission your extension needs, what the mairie is allowed to refuse, how to challenge an opposition or a refusal within the time limits, and what happens if the works are already built without permission.
French planning permission is called an autorisation d’urbanisme. The two everyday forms are the déclaration préalable, a prior declaration for modest works, and the permis de construire, a full building permit for larger works. Both are judged against the plan local d’urbanisme, the PLU, which is the local land-use plan that fixes, street by street, what may be built, how high, how close to the boundary and how much of the plot may be covered. Every French term below is explained where it first appears, all legal references were checked during this run against the official texts, and the practical thresholds given for pools come straight from the current regulations.
I. Do I need a permit for my pool or extension in France?
A. When does my swimming pool need only a prior declaration, and when does it need a full permit?
The starting principle is simple and strict. The statute provides that “Les constructions, même ne comportant pas de fondations, doivent être précédées de la délivrance d’un permis de construire.” (in substance: Buildings, even without foundations, must be preceded by the grant of a building permit.). A swimming pool is a construction even though it is a hole in the ground rather than a building, so it always needs a prior formality; the only question is whether the light procedure or the heavy one applies. The heavy procedure is the default, and the light procedure exists only where the regulations expressly place your pool inside it, so you must prove that you qualify for the declaration rather than assuming it.
For ordinary garden pools the light procedure is the déclaration préalable, the prior declaration, often shortened to DP. The current regulation states that “En dehors du périmètre des sites patrimoniaux remarquables, des abords des monuments historiques et des sites classés ou en instance de classement, les constructions nouvelles suivantes doivent être précédées d’une déclaration préalable, à l’exception des cas mentionnés à la sous-section 2 ci-dessus” (in substance: Outside the perimeter of remarkable heritage sites, the surroundings of historic monuments and classified sites or sites awaiting classification, the following new constructions must be preceded by a prior declaration, with the exception of the cases mentioned in sub-section 2 above). The same article then lists, at item f), “Les piscines dont le bassin a une superficie inférieure ou égale à cent mètres carrés et qui ne sont pas couvertes ou dont la couverture, fixe ou mobile, a une hauteur au-dessus du sol inférieure à un mètre quatre-vingts” (in substance: Swimming pools whose basin has a surface area of one hundred square metres or less and which are not covered, or whose fixed or mobile cover has a height above ground of less than one metre eighty). In practice, the standard British-owned family pool of eight by four metres, uncovered or with a low roller cover, falls squarely inside this declaration: you file a DP with a location plan, a ground plan with dimensions, cross-sections and photographs of the setting, and the mairie has one month to oppose, two months in a protected zone. That publicly available English-language official page describing the declaration procedure is the service-public.fr guide to the prior declaration, which British readers can use alongside the French forms.
The full permis de construire becomes compulsory as soon as your pool leaves that box. A basin larger than one hundred square metres, any pool with a fixed or mobile cover reaching one metre eighty or more above the ground, such as a high pool enclosure or abri haut, and any pool inside a protected perimeter where the declaration regime is excluded all move you into the permit. The permit file is heavier: full architectural plans, landscape integration, drainage and discharge details, and a longer examination period, usually two months outside protected zones and longer within them. Two traps catch British owners here. First, the cover height is measured above the natural ground before works, not above the finished terrace, so a tall enclosure on sloping land can push an apparently modest pool into the permit without you realising it. Second, in zones A (agricultural) and N (natural) of the PLU, pools are frequently refused outright unless they are the annex of an existing lawful dwelling, and a high cover reads as an additional building that the zone never allows. Check the zoning letter of your plot on the PLU map before choosing the size and the cover, because redrawing the project after an opposition costs a season.
Protected surroundings deserve their own warning because they cover far more of France than British buyers expect. The heritage rule provides that “Les travaux susceptibles de modifier l’aspect extérieur d’un immeuble, bâti ou non bâti, protégé au titre des abords sont soumis à une autorisation préalable.” (in substance: Works likely to alter the external appearance of a building, built or unbuilt, protected under the surroundings regime are subject to prior authorisation.). Around every listed monument stretches a 500-metre protection circle in which the architecte des Bâtiments de France, the ABF, the state heritage architect, gives an opinion that is often binding: an unfavourable ABF opinion means the mairie must refuse. Village churches, châteaux, old bridges and historic centres put thousands of British-owned houses inside these circles. A turquoise liner, a raised coping or a pool house visible from the church square can draw an objection that no argument about English taste will move. Ask the mairie at the outset whether the plot lies in a protected perimeter, and if it does, design the pool to disappear: muted liner, level coping, planting screen shown on the landscape sheet, and no pool house in the protected view.
B. When does my house extension need a prior declaration, and when does it need a full permit?
Extensions follow the same two-track logic but through a different doorway. While pools are new constructions governed by the thresholds above, an extension is works on an existing building, and the statute sends you to a list: “Un décret en Conseil d’Etat arrête la liste des travaux exécutés sur des constructions existantes ainsi que des changements de destination qui, en raison de leur nature ou de leur localisation, doivent également être précédés de la délivrance d’un tel permis.” (in substance: A decree in Conseil d’Etat fixes the list of works carried out on existing buildings, and of changes of use, which by reason of their nature or location must also be preceded by the grant of such a permit.). The mirror provision adds that “Un décret en Conseil d’Etat arrête la liste des constructions, aménagements, installations et travaux, y compris ceux mentionnés à l’article 40 de la loi n° 2023-175 du 10 mars 2023 relative à l’accélération de la production d’énergies renouvelables, qui, en raison de leurs dimensions, de leur nature ou de leur localisation, ne justifient pas l’exigence d’un permis et font l’objet d’une déclaration préalable.” (in substance: A decree in Conseil d’Etat fixes the list of buildings, developments, installations and works which, by reason of their size, nature or location, do not justify the requi[rement of a formality]). Put plainly, modest extensions go through the prior declaration and larger ones through the full permit, with the dividing line fixed by floor area, footprint and location in the regulatory tables. Because those tables distinguish urbanised zones covered by a PLU from areas outside them, and because the PLU itself can tighten the national line, never apply an area figure remembered from a forum: read the PLU rule for your zone, measure the existing surface de plancher (floor area) and emprise au sol (ground footprint) as the regulations define them, and add the project to see which side of the line you land on.
The PLU decides more than the procedure; it decides whether the extension is possible at all. Even a small kitchen extension that qualifies for a declaration will be opposed if it breaches the zone’s maximum footprint, the required distance to the boundary, the height limit, the parking quota or the rule on external appearance. Stone villages commonly require matching roof tiles, limited window proportions and no visible render; suburban zones impose three-metre setbacks and planting strips; flood-risk and clay-shrinkage overlays add foundations and floor-level conditions that appear nowhere in the national thresholds. Order a certificat d’urbanisme opérationnel, an operational planning certificate, before paying the builder’s deposit: for a modest fee the mairie tells you in writing, for your exact project on your exact plot, which rules apply, which taxes will be due and whether the land is served by the networks. That certificate does not replace the permit, but it freezes the applicable rules for eighteen months and exposes a hopeless project before it costs you a deposit.
If your French base is in Paris or elsewhere in Île-de-France rather than a holiday village, every paragraph above applies with tighter screws. The competent authority rule states that “L’autorité compétente pour délivrer le permis de construire, d’aménager ou de démolir et pour se prononcer sur un projet faisant l’objet d’une déclaration préalable est :” (in substance: The authority competent to grant building, development or demolition permits and to rule on a project subject to a prior declaration is:), and in any commune covered by a PLU that authority is the mayor in the name of the commune. Paris has its own demanding PLU, the protected perimeters blanket entire arrondissements, roof terraces, mansard extensions and courtyard infills face heritage and overlooking rules that rural owners never meet, and flats add a second layer: the copropriété, the co-ownership, whose general meeting must authorise works affecting the common parts or the external appearance before the mairie even looks at the file. In the inner suburbs the competent court for any later challenge is the administrative court of Paris, Montreuil, Cergy-Pontoise, Melun or Versailles according to the commune, each with its own filing practicalities, so identify your court on the refusal letter the day it arrives. Île-de-France projects also almost always need an architect sooner, disturb neighbours sooner and draw objections sooner, which makes the pre-filing check of the PLU and the co-ownership rules the most valuable hour of the whole project.
Two cost consequences complete the picture and link planning to the annual bills of ownership. A pool and an extension enlarge the taxable base of the property: the taxe foncière, the annual land tax, is reassessed on the improved building, a development tax is levied on the created floor area at the rates voted locally, and the pool must be declared to the tax office within ninety days of completion. The detailed mechanics of those yearly bills, surcharges and exemptions for British-owned second homes are set out in the companion guide to annual property taxes and surcharges on British second homes in France, which you should read alongside this article before fixing the project budget. Builders sometimes present the planning file as included in the price; verify in writing who signs the application, who answers a request for additional documents and who bears the cost of redrawing after an opposition, because a builder who has moved to the next site while your file sleeps is the most common cause of a tacit opposition that could have been avoided.
II. The mairie refused or the neighbour objects: how do I challenge, and what if I built without permission?
A. My declaration was opposed or my permit refused: how do I correct the file, appeal and go to court in time?
A refusal in France is never a spoken word at the counter; it is a written, reasoned administrative decision. The procedure rule provides that “L’autorité compétente se prononce par arrêté sur la demande de permis ou, en cas d’opposition ou de prescriptions, sur la déclaration préalable.” (in substance: The competent authority rules by order on the permit application or, in the case of opposition or conditions, on the prior declaration.). Opposition to a declaration and refusal of a permit must state the precise PLU articles, safety rules or missing documents behind the decision, and an unreasoned or boilerplate refusal is itself unlawful and can be annulled for defective reasoning. Read the order line by line on arrival: the cited PLU article numbers, the quoted setback or footprint figure, the named missing plan, and any attached ABF opinion. Then distinguish the two very different situations that look alike in the letter. A request for additional documents within the first month suspends the examination period and gives you, in practice, three months to complete the file; silence at the end of that period produces a tacit opposition, which is a refusal you can challenge but a refusal all the same. A true opposition or refusal closes the examination, and the two-month court clock described below starts running from its notification.
In most British-owner cases the fastest remedy is not the court but a corrected file. If the opposition points to a remediable defect, an undersized setback drawing, a missing cross-section, a wrong cadastral reference, a cover that tips the pool into the permit, redraw the project to comply and file a fresh declaration or application. A new filing opens a new examination period and, where the defect was technical, succeeds within weeks; it also preserves good relations with a mairie you will need again for the completion certificate. Parallel to that, consider the recours gracieux, the informal appeal to the mayor asking him to withdraw the refusal, which must be lodged within two months and usefully exposes a legal error, a misread plan or a PLU article that does not say what the order claims. The gracious appeal extends the time for the court action if the mayor rejects it or stays silent for two months, but it never replaces the court deadline, so diary both dates from the day the refusal arrives and never let the gracious appeal be the only step. For British readers used to planning inspectors, note the difference: the French gracious appeal goes back to the same mayor who refused, so frame it as a technical correction with plans and photographs, not as a complaint.
The court action is the recours contentieux before the tribunal administratif, the administrative court, and its deadline is rigid. The justice rule states that “La juridiction ne peut être saisie que par voie de recours formé contre une décision, et ce, dans les deux mois à partir de la notification ou de la publication de la décision attaquée.” (in substance: The court may only be seized by way of an appeal brought against a decision, within two months from notification or publication of the contested decision.). Two months from the notification of the refusal or of the rejection of the gracious appeal, not from when you return to France for the summer: a letter collected by your gardien or held at the post office still notifies you. The application must identify the decision, state the grounds, attach the refusal, the file plans, the PLU extract and the evidence that the project complies, and be notified to the mairie as the code requires. Plead in this order: external legality first, defective reasoning, incompetent signatory, procedural error such as a late consultation, then internal legality, error of law on the PLU article, manifest error of assessment on integration, and breach of a higher rule. Ask the court, in the alternative, for partial annulment or for an injunction prescribing what the mayor must do, because judges can now order the authority to grant the permit or re-examine the file within a fixed time rather than simply annulling.
Victory in court carries a valuable shield for the second filing. The statute provides that “Lorsqu’un refus opposé à une demande d’autorisation d’occuper ou d’utiliser le sol ou l’opposition à une déclaration de travaux régies par le présent code a fait l’objet d’une annulation juridictionnelle, la demande d’autorisation ou la déclaration confirmée par l’intéressé ne peut faire l’objet d’un nouveau refus” (in substance: Where a refusal of an application for authorisation to occupy or use land, or an opposition to a works declaration governed by this code, has been judicially annulled, the application or declaration confirmed by the person concerned may not be the subject of a fresh refusal), on the basis of planning rules adopted after the annulled decision, provided the confirmation comes promptly. The supreme courts police this mechanism strictly across the civil-administrative divide. In a leading published ruling the Cour de cassation, the supreme court for civil and criminal matters, held that “s’il n’appartient qu’à la juridiction judiciaire de statuer sur l’action d’une commune tendant, sur le fondement de l’article L. 480-14 du code de l’urbanisme, à la démolition d’une construction irrégulièrement édifiée sur une propriété privée, il appartient à la juridiction administrative de statuer sur l’existence d’un permis de construire tacite, conformément auquel la construction aurait été édifiée, né du silence gardé par l’administration à l’expiration du délai d’instruction de la confirmation de la demande de permis de construire formée par le pétitionnaire sur le fondement de l’article 600-2 du code de l’urbanisme, avant que le jugement d’annulation de la décision qui a refusé de délivrer le permis de construire ne soit définitif.” (Cour de cassation, troisième chambre civile, 27 mai 2021, pourvoi n° 20-23.287, publié au Bulletin). (in substance: while only the civil courts may rule on a commune’s action seeking, on the basis of article L. 480-14 of the town-planning code, the demolition of a building unlawfully erected on private property, it is for the administrative courts to rule on the existence of a tacit building permit, in accordance with which the building is said to have been erected, arising from the administration’s silence at the expiry of the examination period for the confirmation of the permit application made by the applicant on the basis of article 600-2 of the town-planning code, before the judgment annulling the refusal decision became final.). The lesson for British owners is concrete: confirm the application quickly after the annulment, calendar the silence period, keep proof of the confirmation and of the expiry date, and do not build a day early, because the tacit permit born of silence is real but its birth date will be litigated.
Neighbours add a second front that surprises British owners who assume only the mairie matters. A neighbour with standing, typically an adjoining owner who can show the project affects the use of his own property, may challenge a granted permit or a non-opposed declaration before the same administrative court within strict time limits running from the publicity of the permission, which is why the regulations require you to display the permit panel on the land continuously and to keep the bailiff’s report or dated photographs proving it. Keep the display up for the whole period without interruption, because a missing panel restarts the neighbours’ clock. Conversely, if you are the British owner objecting to a neighbour’s block of flats that will stare into your pool, act within days: photograph the panel, note its first day of display, obtain the file from the mairie, and file your own gracious appeal and court action inside the same short limits. Practical guidance on daily administrative life in France, including residence and access to services that frame any long dispute, is kept updated in the British government’s living in France guide, which you should consult for the non-legal logistics while the legal deadlines above govern the dispute itself.
B. I built without permission or against the rules: fines, demolition and how do I regularise?
Building without the required permission or departing from the granted plans is a criminal offence, not a paperwork oversight. The penalty provision states that “Le fait d’exécuter des travaux mentionnés aux articles L. 421-1 à L. 421-5 et L. 421-5-3 en méconnaissance des obligations imposées par les titres Ier à VII du présent livre et les règlements pris pour leur application” (in substance: Carrying out works mentioned in articles L. 421-1 to L. 421-5 and L. 421-5-3 in breach of the obligations imposed by titles I to VII of this book and the regulations made for their application) is punishable by a fine running from 1,200 euros up to a ceiling calculated on the value of the works or the surface concerned, with daily penalties per square metre for continued offending and, for repeat or serious cases, imprisonment provided by the same chapter. The mairie, the prefect’s services and sworn inspectors may enter, record and seal; obstructing them is itself an offence, since “Le fait de faire obstacle aux fonctions exercées par les autorités, fonctionnaires et agents habilités à exercer les missions de contrôle administratif prévues au chapitre Ier du titre VI du présent livre ou de recherche et de constatation des infractions prévues par le présent code est puni de six mois d’emprisonnement et de 7 500 € d’amende.” (in substance: Obstructing the duties performed by the authorities, officials and officers empowered to carry out the administrative inspection tasks provided for in chapter I of title VI of this book, or to investigate and record the offences provided for by this code, is punishable by six months’ imprisonment and a 7,500 euro fine.). Never refuse entry, never remove seals and never instruct the builder to carry on after an interruption order: each of those reactions converts a regularisable pool into a prosecution file.
Beyond the fine, the court can order the physical outcome owners fear most. The enforcement provision allows the criminal judge, in addition to the penalty, to order that the site or the works be brought into conformity, demolished or the land restored, under a daily financial compulsion known as an astreinte for every day of delay. The nature of that order matters enormously, and the Cour de cassation clarified it in 2025: “la mise en conformité des lieux ou des ouvrages, la démolition de ces derniers ou la réaffectation du sol, prévues par l’article L. 480-5 du code de l’urbanisme, constituent des mesures à caractère réel destinées à faire cesser une situation illicite et non des sanctions pénales.” (Cour de cassation, chambre criminelle, 18 mars 2025, pourvoi n° 24-82.569). (in substance: Bringing the premises or works into conformity, demolishing them or restoring the use of the land, provided for by article L. 480-5 of the town-planning code, are measures of a real nature intended to end an unlawful situation and not criminal punishments.). Because demolition is a restorative measure rather than a punishment, it follows the land into whoever’s hands it passes, survives arguments about good faith or the money spent, and can be pursued even where the fine itself is modest. A British seller who conveys an unpermitted pool or extension without declaring it therefore transmits the demolition risk to the buyer, and a British buyer who discovers the pool has no permission after completion inherits the same risk with the title.
The commune has its own civil route that runs alongside any prosecution. The civil-action provision states that “La commune ou l’établissement public de coopération intercommunale compétent en matière de plan local d’urbanisme peut saisir le tribunal judiciaire en vue de faire ordonner la démolition ou la mise en conformité d’un ouvrage édifié ou installé sans l’autorisation exigée par le présent livre, en méconnaissance de cette autorisation” (in substance: The commune or the intercommunal body competent for the local land-use plan may apply to the civil courts to have ordered the demolition or bringing into conformity of a structure erected or installed without the authorisation required by this book, or in breach of that authorisation). This action belongs to the commune even if the public prosecutor never prosecutes, and it targets the current owner, British or French, whether or not he personally built the works. The counterpart protection is narrow and conditional: “Lorsqu’une construction a été édifiée conformément à un permis de construire :” (in substance: Where a building has been erected in accordance with a building permit:), the owner can only be ordered by the civil courts to demolish for breach of planning rules if that permit was first annulled by the administrative courts, and in most locations only for breaches in sensitive zones. Keep the stamped compliant plans, the completion declaration and the certificate of conformity with the title deeds forever: they are the only proof that what stands matches what was allowed, and buyers, notaires and insurers will ask for them on every future sale.
Regularisation is possible but only on the mairie‘s terms and only where the PLU would have allowed the project. Stop the works the moment an illegality is identified, take dated photographs of the exact state, and commission a measured survey showing what was built against what the PLU allows: a pool moved one metre from the boundary or a cover lowered below the threshold often turns an impossible file into a grantable one. Then file the permission that should have been sought, declaration or permit, describing the existing state honestly rather than disguising built works as a future project; case officers detect disguised retrospective files instantly, and dishonesty forfeits the goodwill on which discretionary points turn. If the project as built cannot comply, apply for the compliant variant and offer the demolition of the excess in the file, because a judge asked later to order demolition routinely checks whether the owner attempted conformity first. Complete the tax declaration for the regularised works, inform the house insurer in writing with the granted permission attached, and keep every receipt: the fine may still come, but a documented return to legality is the difference between a fine with conformity and a fine with demolition under astreinte.
Conclusion
A pool or an extension on a British-owned French house is a two-permit question answered by the PLU, not by English instinct. Pools within the one-hundred-square-metre, low-cover box go through the prior declaration; anything bigger, taller or inside a protected perimeter needs the full permit with the heritage architect’s binding voice. Extensions on the existing house divide along the regulatory tables between the declaration and the permit, and the PLU’s footprint, setback, height and appearance rules can refuse either track whatever the national thresholds suggest. Paris and Île-de-France tighten every screw through the capital’s PLU, omnipresent protected sectors and co-ownership votes that must come before the mairie file. An opposition or refusal must be reasoned and arrives as an arrêté; correct and refile where the defect is technical, lodge the gracious appeal and the administrative court action inside the two-month limits, confirm promptly after any annulment to earn the freeze on later rules, and display every granted permission without interruption to close the neighbours’ clock. Building without permission risks the criminal fine, obstructing inspectors adds imprisonment and a fixed fine, and the demolition or conformity order follows the land as a restorative measure whether or not the prosecutor acts, with the commune free to sue the current owner directly. Check the PLU first, file the right procedure with complete plans, keep the stamped permissions with the deeds, declare the works to the tax office, and regularise honestly at the first sign of trouble: that sequence is what turns a French pool and a larger kitchen from a litigation file back into what they should be, the reason you bought the house.