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 a PLU (plan local d'urbanisme, the commune's local zoning plan), any extension over 20 m² of surface de plancher (floor area) or emprise au sol (ground footprint) needs a PC. In an urban zone (zone U) of a PLU, the DP threshold stretches to 40 m². Most Riviera villas sit in a zone U, but check the zoning of your plot before assuming the 40 m² figure.

There is a second trigger that catches renovations which would otherwise stay under a DP: a PC is required for any extension between 20 and 40 m² that takes the property's total surface de plancher past 150 m². A 25 m² veranda on a house already at 130 m² crosses that line even though 25 m² is under the 40 m² DP threshold.

A PC is also required for new construction, and for a change of destination (turning a garage into living space, for example) when the work touches load-bearing structure or the facade. A change of use with no structural or facade work can often stay at DP level; check with 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 becomes compulsory once the project takes the building's total surface de plancher past 150 m². Below that figure, you can file the PC yourself or have your contractor prepare the drawings.

That threshold does not apply when the applicant is a company. If you are filing through an SCI (société civile immobilière, the property-holding company structure some second-home owners use), an architect is required whatever the surface, with no exemption. Worth checking before you assume the 150 m² rule covers you: the applicant's legal status decides it.

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

For a house, standard instruction time is two months from the date the mairie confirms your file is complete. That extends to three months if the property sits within an ABF (Architecte des Bâtiments de France) perimeter, the heritage protection zones that cover much of the historic centre and coastline on the Riviera. The mairie can pause the clock once to ask for missing documents, which resets the countdown from the date you resubmit.

The application form is the Cerfa PCMI (permis de construire maison individuelle) declaration used for a house and its outbuildings. Once granted, the permit must be displayed on-site (affichage) on a panel at least 80 cm on its shortest side, visible from the road, for the full construction period.

That display starts the two-month recours des tiers window, the period during which a neighbour or third party can legally challenge the permit. Start work before the display has run its two months and you carry the risk that a late challenge disrupts a project already underway.

A granted PC is valid for three years and can be extended twice, one year at a time, if you request the extension before it lapses. When the work is finished, you file a DAACT (déclaration attestant l'achèvement et la conformité des travaux), confirming the completed building matches what was approved. The mairie can inspect within three months of that filing, and a notaire will ask for the DAACT at resale.

Permis de construire in copropriétés and protected zones

In a copropriété (a jointly-owned apartment building or shared-ownership development), a PC application for work on the exterior or common structure needs the copropriété's authorisation, voted at the general assembly (assemblée générale), before you file with the mairie. The permit itself is still a matter between you and the commune, but the mairie can ask to see the copropriété's consent as part of the file.

Inside an ABF perimeter, the ABF's approval is required alongside the mairie's, which is what pushes instruction from two months to three. The ABF can set conditions on materials, colours, or roof shape, and can refuse a design on heritage grounds even where the underlying zoning would otherwise allow it. If your project sits near a listed building or inside a designated heritage zone, get the ABF's informal view on the design before finalising drawings: a refusal after months of planning costs far more than an early conversation.

Related terms

• 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
• 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