Permis de construire: the full building permit for larger renovation work

When does a renovation need a permis de construire instead of a DP?

Outside an urban zone, any extension over 20 m² needs a PC. That counts either new floor area (surface de plancher) or new ground footprint (emprise au sol). In an urban zone (zone U) of the commune's PLU, its local zoning plan, the DP limit rises to 40 m². Most Riviera villas sit in a zone U, but ask the mairie to confirm your plot's zoning before you rely on the 40 m² figure.

A second rule catches projects that would otherwise stay under a DP. An extension of 20 to 40 m² needs a PC if it takes the house past 150 m² in total. A 25 m² veranda on a 130 m² house crosses that line, even though 25 m² is under the 40 m² limit.

New construction always needs a PC. So does a change of use, such as turning a garage into living space, when the work touches the load-bearing structure or the facade. Without that work, a change of use can often stay at DP level. Ask the mairie's service urbanisme (planning department) before assuming either way.

Do you need an architect for a permis de construire?

For a private individual, an architect is compulsory once the project takes the building past 150 m² of floor area. Below that, you can file the PC yourself or have your contractor prepare the drawings.

The 150 m² exemption doesn't apply to a company. If you own through an SCI (société civile immobilière, the property-holding company some second-home owners use), you need an architect whatever the size. Check who the legal owner is before you plan to file without one.

How long does the mairie take and what happens after approval?

For a house, the mairie has two months from the date your file is complete. That becomes three months inside an ABF perimeter, the heritage zones around listed buildings that cover much of the Riviera's historic centres. The mairie can ask once for missing documents, and the clock restarts when you supply them.

Once granted, the permit must be displayed on site for the whole build. The panel has to be at least 80 cm on its shortest side and visible from the road. The display starts a two-month window in which a neighbour or other third party can challenge the permit. If you start work before those two months are up, a late challenge can halt a project that's already underway.

A PC is valid for three years and can be extended twice, one year at a time, if you ask before it lapses. When the work is done, you file a DAACT (déclaration attestant l'achèvement et la conformité des travaux, the declaration that the work is finished and compliant), confirming the building matches the permit. The mairie then has three months to inspect, or five in some protected heritage areas and mapped risk zones. Keep the DAACT, because the notaire (notary) will ask for it when you sell.

Permis de construire in copropriétés and protected zones

In a copropriété (a jointly owned apartment building or estate), work on the outside or the shared structure needs a vote at the general assembly (assemblée générale) before you file. The permit is still between you and the commune, but the mairie can ask to see the copropriété's consent.

Inside an ABF perimeter, the ABF must agree as well as the mairie, which is why the wait goes from two months to three. The ABF can set conditions on materials, colours or roof shape. It can also refuse a design on heritage grounds even where the zoning allows it. Near a listed building, ask the ABF for an informal view before the drawings are finished. A refusal after months of design work costs far more than an early meeting.

More on French building permits and planning thresholds

• Déclaration préalable de travaux: the lighter planning notification used below the permis de construire thresholds
• DPE: the energy performance certificate that can influence renovation scope and financing
• Whole-house renovation: extensions and structural work that can cross the permis de construire threshold
• Outdoor & pools: pool houses, verandas, and outbuildings that add surface de plancher
• Insulation & windows: facade-changing work such as external wall insulation, which can require a déclaration préalable or, on a larger project, a permis de construire