Planning permission in France: déclaration préalable vs permis de construire
A new window. A garden shed. A pool for the children. A barn crying out to be a bedroom. In Britain much of this is permitted development you'd never think twice about — in France, a surprising amount of it needs the commune's blessing first, and doing it in the wrong order is how good renovations turn into expensive regrets. The system isn't hostile, and it's genuinely logical once you see it, but it catches almost every British arrival out at least once. Here's how French planning permission actually works: which consent your job needs, what the numbers are, how the process runs, the tax that follows — and why you must never, ever build first and ask later.
The short version
- Two consents. A light déclaration préalable (DP) for small works and changes of appearance; a full permis de construire (PC) for anything substantial.
- The magic numbers: nothing under 5 m², a DP from 5 to 20 m² (up to 40 m² for an extension in a town with a local plan, or PLUThe plan local d'urbanisme — your commune's local planning map and rulebook. It sets what can be built where, at what height, and in which materials and colours. Two neighbouring plots can carry very different rules.), a permis above that — and an architect once the total tops 150 m².
- Even a new window or a re-render needs a DP — changing the exterior look is the commune's business.
- Check the PLU and get a certificat d'urbanisme before you buy a project — the zoning decides what's ever possible.
- Silence often means yes — but get written confirmation, display the site board, and keep every stamped form for when you sell.
- Never build without asking. The penalties run to forced demolition and fines per square metre, and undeclared work can sink a future sale.
Every British renovator in France remembers the moment the penny dropped: that the shed, the extra window, the pool, the knocked-through barn — jobs you'd have cracked on with at home — first have to pass by the mairieThe town hall — the first port of call for a huge range of local admin.. It feels heavy-handed at first. But French planning has a clear internal logic: the outside of a building, and how it sits in its village, is treated as a shared thing, so the commune gets a look before you change it. Get your head around two consents and a handful of numbers and the whole system falls into place — and, done right, it's rarely the ordeal newcomers fear. Let's start with the fork in the road: which permission your project actually needs.
Which one do you need? DP vs permis de construire
Almost every job lands as one of three things: no formality, a déclaration préalable, or a permis de construire. Which one is decided mostly by surface — but the type of work matters too. Here's the map, then the detail. Open each.
The DPDéclaration préalable — the light-touch one
A déclaration préalable de travaux (DP) is the lighter of the two consents — a declaration you file and, if the mairie doesn't object within the deadline, you may proceed. It covers small works and changes of appearance: a modest extension, a garden shed, most swimming pools, new or altered windows, a change of roof or render, solar panels, a fence, or dividing a plot. It's a single Cerfa form with plans and photos, and the instruction period is usually just one month. Think of it as 'telling the commune, and giving it a chance to say no.'
The PCPermis de construire — the full permit
A permis de construire (PC) is the proper building permit, needed for anything substantial: a new house, a larger extension, a major change of use with structural work, or anything taking you over the surface thresholds below. The dossier is heavier (fuller plans, a site plan, a description of materials and how the building sits in its surroundings), and the wait is longer — two months for a house, three for most other projects, and often a month more where a protected zone brings the architect of French heritage into it. Over 150 m² of total floor area, you must use an architect.
5 / 20 / 40 / 150The surface thresholds, in plain numbers
The line between the two is drawn by surface — measured as either surface de plancher (enclosed floor area) or emprise au sol (ground footprint), whichever is greater. A brand-new detached building or shed needs nothing up to 5 m², a DP from 5 to 20 m², and a PC above 20 m². For an extension to an existing house, the DP ceiling jumps to 40 m² if you're inside a town covered by a PLU (the commune's local planning rulebook) — but only 20 m² outside one. And whatever the extension size, if it pushes the total over 150 m², you need a permis and an architect. The diagram above is your ready-reckoner.
The common jobsPools, sheds, fences and changing the look
The jobs Britons most often get caught by. A swimming pool: no formality for a basin up to 10 m², a DP from 10 to 100 m², a PC above that — and a pool shelter 1.80 m or higher needs a permis whatever the basin size. A garden shed or carport follows the 5 / 20 m² rule like any building. A fence or wall often needs a DP, especially in protected areas or where the commune requires it — ask the mairie. And crucially, changing the exterior appearance at all — a new window, different shutters, a colour, a re-render, swapping the roof tiles — needs a DP even if nothing gets bigger. The outside of your house is, in French law, partly the commune's business.
The thing that surprises Britons most
No answer? You've probably been approved — but don't take the risk
Coming from a British system where planning silence means nothing, arrivals are stunned to learn that in France a lack of reply usually counts as a yes: if the mairie doesn't object within the instruction deadline, your DP becomes a non-opposition and your permit a permis tacite, and you may lawfully proceed. It's a genuine mercy in a country famous for paperwork. But treat it with care — protected heritage zones are an exception where silence can cut the other way, and a future buyer's notaireA state-appointed legal officer who handles property sales and estates. will want proof. So even when you're sure the deadline has passed, go to the mairie and ask for a written certificat de non-opposition. It costs nothing and it's the document that lets you build, and later sell, without a cloud over the work.
Major building work? You may legally need dommages-ouvrage cover
For structural work, French law effectively expects an assurance dommages-ouvrage — it pays to put defects right fast without waiting to apportion blame, and its absence can haunt a future sale. Alongside it, using artisans who carry the ten-year garantie décennale protects you. Both are worth lining up before the first wall moves.
Compare renovation cover →Pimpernel may earn a small commission if you use this — it never changes what we recommend, and there's nothing to sell you.
Before you touch anything: zoning and the CU
The forms come second. What decides whether a project is possible at all is the zoning — and there's a free piece of paper that tells you where you stand before you commit a euro. This is the part that saves people from buying a lovely wreck they'll never be allowed to change. Open each.
Local rulesThe PLU decides what you can actually do
Before size, before forms, comes zoning. That PLU has a full name — the plan local d'urbanisme — and it's the local planning map and rulebook that says what may be built where, in what materials, at what height, and what colour. Some smaller communes use a simpler carte communale, and a few fall back on the national RNU. Two plots next to each other can carry very different rules, and the PLU is where dreams of a glass extension or a second dwelling quietly live or die. It's public — ask at the mairie or find it online — and worth reading before you fall in love with a project.
Do this firstThe certificat d'urbanisme — ask before you buy
The single most useful piece of paper for anyone buying a project. A certificat d'urbanisme (CU) is a free request to the mairie that tells you the rules on a plot: the informational CUa sets out the applicable rules and taxes, while the operational CUb tells you whether a specific project is feasible. Get one before you sign for a barn to convert or a garden to build on — it freezes the rules in your favour for 18 months, and can save you from buying a ruin the commune will never let you touch.
ABFProtected zones and the Architecte des Bâtiments de France
If your property is near a monument historique, in a site patrimonial remarquable, or in certain villages and conservation areas, the Architecte des Bâtiments de France (ABF) gets a say. That means stricter rules on materials, tile types, window styles and colours, a longer instruction period, and sometimes a firm 'non' to modern touches. It's not there to torment you — it keeps French villages looking the way you fell for — but budget the extra time and expect to use traditional materials. Ask the mairie early whether the ABF is involved; it changes what's realistic.
The process, and the paper trail after
Once you know which consent you need, the mechanics are straightforward and mostly predictable. The trick is knowing the sequence — file, wait, display, build, close — and keeping the evidence at each step. Open each.
Le dépôtFiling — online or at the mairie
You file the relevant Cerfa form with its plans and photos. Since 2022, every commune of 3,500+ residents must accept online submission (a guichet numérique or the national portal); smaller communes may still take paper in duplicate at the mairie counter. Either way, keep your dated receipt — the instruction clock starts from a complete dossier, and the mairie has one month to ask for anything missing.
1–3 monthsThe wait — and the silence that often means yes
Instruction runs about one month for a DP and two to three months for a permis. Here's the part that startles arrivals: if the deadline passes with no reply, you're usually granted by default — a non-opposition (DP) or a permis tacite (PC). Silence means yes. But not always — protected (ABF) zones are a notable exception, where silence can mean the opposite — so always ask the mairie for a written certificat de non-opposition as proof before you start or sell.
Affichage + recoursDisplay the panneau, then the two-month clock
Once granted, you must display a site board (the panneau d'affichage, at least 80 cm, visible from the road) for the whole of the works and for a continuous two months minimum. That display starts the neighbours' appeal window (recours des tiers): for two months, a third party can challenge your permit. Photograph the board up, dated, so you can prove it was shown — it's your protection against a late objection.
Start & finishDOC and DAACT — opening and finishing
Two more forms bracket a permis. When work begins you file the DOC (déclaration d'ouverture de chantier); when it's finished you file the DAACT (déclaration attestant l'achèvement et la conformité des travaux), certifying it was built as permitted. The mairie then has three months (more in some zones) to inspect. Keep the stamped DAACT safe — you'll be asked for it when you sell, as proof the work was legitimate.
Not sure if it's a DP, a permis, or nothing at all?
The thresholds, the zoning, the Cerfa forms, the ABF question — working out which consent a job actually needs is exactly where British renovators lose weeks (or build something they shouldn't have). Pimpernel can help you read your PLU, judge the right form, and get the dossier straight before it goes anywhere near the mairie.
The taxe d'aménagement — the bill that follows the permit
Here's the one that ambushes people a year later. Most works that create surface — an extension, a shed over 5 m², a pool — trigger a one-off taxe d'aménagement (development tax), billed by the tax office after completion. It's worked out on a national per-square-metre value set each year, multiplied by your local rates. For 2026 the base value is €892/m² outside the Paris region (€1,011/m² within it) — and, unusually, that's a fall of around 4%, the first drop in nine years. Swimming pools have their own fixed value of €251/m² of basin. On top sits your commune's rate (typically 1–5%) plus a departmental rate (up to 2.5%), with a 50% reduction on the first 100 m² of a main home. In real terms: a modest pool might bring a few hundred euros; a decent extension, four figures. It's declared to the tax office within 90 days of finishing (through the Gérer mes biens immobiliers service on impots.gouv.fr), and for larger bills you can pay in instalments — but budget for it from the start, because it lands whether or not you saw it coming.
Renovation runs on deadlines and paperwork
The certificat d'urbanisme, the DP or permis, the month the mairie can query it, the two-month panneau, the DOC and DAACT, the taxe d'aménagement instalments — a renovation is a string of dated jobs where a missed one costs real money. Pimpernel Pro keeps the whole sequence on a plan so nothing lapses and nothing gets built without cover.
- Planning-deadline reminders
- The property & renovation guides
- Cerfa & document checklists
- Every Library guide, in depth
The one thing not to do: build without asking
It's tempting. The shed is small, the barn is round the back, nobody will notice. Resist it — this is the mistake that turns a project into a nightmare. Building without the required consent is an infraction, and the consequences are real: the courts can order you to demolish or regularise at your own cost, and the fine runs from roughly €1,200 to €6,000 per square metre. The criminal exposure lasts six years from completion, and a neighbour can bring a civil claim for up to ten. Worse for most people is the quiet trap at the other end: when you come to sell, the notaire and the buyer will want proof that every visible change was authorised. Undeclared works can knock thousands off the price, delay or collapse a sale, or leave the buyer able to come after you afterwards. A weekend saved now is not worth a sale lost later. If something was built before your time and you're unsure it was ever declared, ask the mairie and, where you can, regularise it — a retrospective DP or permis is far cheaper than the alternative.
Buying a project in the first place?
The purchase, the notaire, the fees and the surveys — our buying guide walks British buyers through it before you sign for that barn.
Read: Buying property in France →Doing up a rural place?
Water, waste, heating and the realities of an old country house — our rural-life guide covers what a renovation really takes on.
Read: Rural life in France →Straight from the source
Read the official rules for a déclaration préalable (F17578) or a permis de construire (F1986) on service-public.fr, the taxe d'aménagement detail on economie.gouv.fr, and your plot's zoning via your mairie's PLU.
The thresholds, timeframes, tax values and penalties here are current for 2026 and drawn from official and specialist sources, but planning is deeply local: your PLU, your zone, the involvement of the Architecte des Bâtiments de France and your commune's own rates all change what applies to a specific plot. Pimpernel are not architects, surveyors or planning lawyers. Confirm your project with your mairie and, for anything substantial, a French architect or maître d'œuvre before you act. This guide is general information, not planning advice.