Buying Guide
Renovating property in France
Permis de construire or déclaration préalable? The permissions, thresholds and costs foreign owners need before extending or renovating in the Alpes-Maritimes.
What permission do you need to renovate in France?
Quick answer: It depends on the surface you create and your zone. Adding up to 5 m² usually needs nothing; 5–20 m² (or up to 40 m² in a PLU urban zone) needs a déclaration préalable; above that you need a permis de construire. An architect is mandatory whenever the work takes the total floor area over 150 m², or the existing house is already over 150 m². In protected village cores you also need the Architecte des Bâtiments de France (ABF) sign-off.
French renovation rules turn on two things: how much new floor area (surface de plancher or emprise au sol) you create, and what your commune’s local plan (PLU) allows on your plot. Most of the eight hinterland villages have a PLU, so the higher thresholds apply inside their urban zones — but the historic cores carry extra protection. This guide is current as of June 2026; always confirm the specifics with your mairie before you commit.
This is a planning overview, not legal advice
Thresholds below are the national rules from service-public.fr. Your plot may carry stricter local rules (PLU, protected perimeter, flood/wildfire zone). Always check with the mairie’s service urbanisme and, for anything structural, an architect or maître d’œuvre. Verify before you buy if a renovation is central to your plan.
Déclaration préalable vs permis de construire
Quick answer: New floor area decides it — under 5 m², nothing; 5–20 m² (40 m² in a PLU urban zone), a déclaration préalable; over that, a permis de construire. A déclaration préalable also covers most façade changes, roof works, pools up to 100 m² and changes of use without structural work.
| Project | Permission | Typical decision time |
|---|---|---|
| New floor area ≤5 m² | Usually none | — |
| Extension 5–20 m² (≤40 m² in PLU urban zone) | Déclaration préalable | ~1 month |
| Extension >20 m² (>40 m² in PLU urban zone) | Permis de construire | ~2–3 months |
| Any work taking the total >150 m² | Permis de construire + architect | ~2–3 months |
| Façade change, new openings, roof, pool ≤100 m² | Déclaration préalable | ~1 month |
| Interior works, no surface or façade change | Often none | — |
Source: service-public.fr (déclaration préalable F17578, recours à un architecte F20568), national thresholds as of June 2026. A déclaration préalable is valid 3 years; a refusal can be appealed within 2 months. Protected perimeters and specific PLU rules can change which applies.
The 150 m² architect rule and protected villages
Quick answer: You must appoint an architect once a project takes the total floor area over 150 m², or if the existing house already exceeds 150 m². In the historic cores of villages like Valbonne, Biot, Mougins and Grasse, works visible from a protected monument or perimeter also need the Architecte des Bâtiments de France (ABF) to sign off — which can dictate materials, colours and even shutter type.
Architect (above 150 m²). For individuals, the architect requirement bites when the completed floor area exceeds 150 m² — a common trigger when extending an already-large villa. An architect is never required for a project that only needs a déclaration préalable. Budget architect fees at roughly 8–12% of works for a full design-and-supervision brief.
Protected perimeters (ABF). Many hinterland village cores sit within the protection perimeter of a classified monument or are sites patrimoniaux remarquables. Inside these zones the ABF must approve the appearance of any visible works — façades, roofs, openings, render colour, even pool fencing. ABF review adds time and constrains design, so factor it in early; your mairie will tell you whether your address is affected.
Wildfire and flood overlays. Parts of the Alpes-Maritimes hinterland carry PPRIF (wildfire) or flood-risk overlays that impose débroussaillement (brush-clearing) obligations and can restrict building. These are checkable on the commune’s plan de prévention des risques.
Energy upgrades, taxe d’aménagement and budgeting
Quick answer: Creating new surface triggers a one-off taxe d’aménagement, paid to the commune and département. Energy upgrades matter for resale and letting — France is phasing out the worst-rated homes from the rental market — so a poor DPE is both a price lever and, if you plan to let, a hard constraint.
- Taxe d’aménagement. A one-off tax due when you create floor area (extension, pool, outbuilding), calculated on the surface created times an annually-revised national base value times the commune and département rates. See economie.gouv.fr. Pools and large outbuildings are caught.
- DPE and the rental phase-out. If you intend to let, note France’s energy-performance phase-out of the worst-rated homes from the long-term rental market (G-rated already restricted; F and then E following). A weak DPE also discounts resale. See our selling guide for the audit-énergétique timeline.
- Use RGE artisans. Energy-renovation grants and reduced VAT generally require RGE-certified tradespeople; most national grants target tax residents and primary residences, so non-resident second-home owners should not assume eligibility.
- Build a contingency. On older village stone houses, budget a 10–15% contingency for the surprises that hide behind old walls, and get firm devis before exchange if the renovation is essential to your numbers.
The renovation process, step by step
- Check the PLU and risk plans at the mairie before you buy or design — they tell you what is buildable and which overlays apply.
- Design and choose your permission — déclaration préalable or permis de construire, appointing an architect if you cross 150 m².
- File at the mairie (or online via the commune’s portal). Expect ~1 month for a DP, ~2–3 months for a PC, longer where ABF review applies.
- Display the panel on site once granted; a two-month third-party appeal window runs from display.
- Build with insured, ideally RGE, artisans, keep the devis and factures, and file the déclaration d’achevement (DAACT) at completion.
Planning a purchase with renovation in mind? Pair this with the complete guide to buying in France as a foreigner and the full cost of buying, and use the valuation tool to sanity-check the post-renovation value. Talk to our team for local architect and artisan introductions.
Frequently Asked Questions
Frequently Asked Questions
Interior works that change neither the surface nor the façade usually need nothing. Creating 5–20 m² (up to 40 m² in a PLU urban zone), or changing the façade, needs a déclaration préalable; larger extensions need a permis de construire. Protected village cores add an Architecte des Bâtiments de France review.
For individuals, an architect is mandatory once the project takes the total floor area above 150 m², or if the existing house already exceeds 150 m². An architect is never required for a project that only needs a déclaration préalable (source: service-public.fr, June 2026).
Roughly two to three months for a standard house permit, and about one month for a déclaration préalable. Add time where the Architecte des Bâtiments de France must review (protected perimeters). After approval, a two-month third-party appeal window runs from the date the site panel goes up.
Often yes, but the historic cores carry extra protection: works visible from a classified monument or within a protected perimeter need Architecte des Bâtiments de France approval, which can dictate materials and colours. Check your exact address with the mairie’s urbanisme service before designing.
A one-off tax due when you create floor area — an extension, pool or outbuilding. It is the surface created times an annually-revised national base value times the commune and département rates, paid after the permit is granted. Verify the current base value and local rates with your mairie.
Most national energy-renovation grants target French tax residents and primary residences, so non-resident second-home owners should not assume eligibility. Reduced VAT and some schemes still require RGE-certified tradespeople. Confirm your situation with an accountant before relying on any grant.
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