Three similar structures, three different rules — and, in Toulouse, an extra layer that can remove the exemption altogether. Here is what to check before ordering anything. The rules quoted here were checked in September 2026; they change, and your town hall (mairie) remains the authority that decides.
Before the thresholds: two areas not to confuse
Almost every mistake starts here. Two different measurements are used to size a project, and they do not give the same result for a shed, a carport and a pergola.
Footprint (emprise au sol) is the vertical projection of the building’s volume, including overhangs and projections. A pergola or a carport, even fully open, creates footprint.
Floor area (surface de plancher) only counts enclosed, covered areas with a ceiling height above 1.80 m. An open carport creates none; an enclosed shed does.
In practice: a 25 m² carport and a 25 m² shed are not treated the same way, either for permission or for the tax that follows.
A free-standing structure in the garden
This covers the shed at the bottom of the garden, the free-standing carport and the self-supporting pergola.
- Up to 5 m² of footprint: no formality — unless the work changes the external appearance of an existing building, and except in a protected area, where this exemption does not apply.
- From 5 to 20 m²: prior declaration (déclaration préalable).
- Above 20 m²: full planning permission (permis de construire).
A structure attached to the house
As soon as the structure leans on the house — a lean-to, an attached carport, a store against the gable — the rules change, and they become more favourable in town.
- In an urban zone of a local development plan (PLU), which covers most of Toulouse, a prior declaration is enough up to 40 m².
- Above 40 m²: full planning permission.
- Outside urban zones, the limit drops back to 20 m².
One further threshold is worth knowing: if the extension takes the total floor area of the house above 150 m², planning permission is required again — and that is also the threshold at which using an architect becomes compulsory. On a house that is already large, a modest lean-to can therefore trigger both. And if your project is an extension, the choice of building method is a separate question: see our comparison of a timber frame or concrete block extension.
What Toulouse adds
The PLUi-H, which decides the form
The national thresholds tell you whether an application is needed. The intercommunal local development plan of Toulouse Métropole (PLUi-H) tells you what you are allowed to build: distance from boundaries, maximum height, permitted footprint, appearance of materials, share of the plot to be kept as open ground. These rules vary from one zone to another, sometimes from one street to the next. There is no general answer: there are the rules for your zone, to be checked before drawing anything.
The protected heritage area, which changes everything
Toulouse has a protected heritage area (site patrimonial remarquable) established in 1986. Within its boundary, any work that changes external appearance requires permission — including work that would be exempt elsewhere — and permission is only granted after the opinion of the Architecte des Bâtiments de France, the State’s heritage architect.
In other words: a 4 m² shed visible from the street may need a full application in one neighbourhood, and none at all two kilometres away. This is the first thing to check, even before measuring.
Where to submit the application
Toulouse has an online planning service that lets you apply once you have created an account. Private individuals can still apply on paper, at the city’s planning permission department, which also gives advice beforehand. A ten-minute call before drawing can save you a refusal.
Neighbouring municipalities each apply their own rules: the national thresholds do not change, but siting, height and appearance do.
Timescales, and what they mean for your schedule
| Situation | Processing time |
|---|---|
| Prior declaration, general case | 1 month |
| Prior declaration in a protected area | 2 months — the town hall notifies you within the first month |
| Planning permission, detached house and outbuildings | 2 months |
| Planning permission in a protected area | 3 months |
If the application is incomplete, the town hall has one month to request the missing documents; you then have three months to provide them, and the processing time starts again from zero. For a prior declaration, no reply within the deadline counts as tacit approval: you can ask for a certificate confirming it.
Once permission is granted, three points matter as much as the rest. It is valid for three years, and lapses if work stops for more than a year. Displaying the permission on site is compulsory for the whole duration of the work, on a rectangular sign at least 80 centimetres across, visible from the public road. And third parties have two months to appeal, counted from the first day of two months’ continuous display.
In terms of a building schedule: a shed decided on in spring, in a protected area, with the appeal period cleared before starting, will not go up before summer. That is no reason to give up; it is a reason to start early.
And the development tax?
It comes afterwards, and it often comes as a surprise. The taxe d’aménagement is due on enclosed, covered areas created with a height above 1.80 m, beyond 5 m². It is calculated on a flat-rate value per square metre revised every year and on locally voted rates, and it must be declared within ninety days of completion, through your personal account on the French tax website.
The open carport is a special case: it creates no enclosed, covered area, but the tax also includes a flat charge per parking space. This is a point to have confirmed by the tax office or with the official planning tax simulator, rather than assumed.
What we do, and what we do not do
We design the structure with these constraints in mind — height, siting, appearance — and we provide the technical documents for the application: plans, sections, description of materials. That is the carpenter’s job, and it is best done before cutting.
Submitting the application and following it up remain in your hands. We are neither a planning consultancy nor an architect’s practice, and saying so from the outset saves you expecting from us what we do not do.
Let’s talk about your project
A shed, a carport or a lean-to is decided much earlier than people imagine: planning rules affect the height, the siting and sometimes the timber species visible from the street. Better to talk about it before the drawing than after a refusal.
Tell us about your project and your address: we will tell you what the structure involves, we prepare the technical documents required, and we provide a detailed, free, no-obligation quote.
Article checked in September 2026. Thresholds, timescales and amounts change. Before applying, check the official information currently in force and ask your local planning department: it is the one that decides.
