Buying and renovating in France: 11 mistakes that can blow your budget

Think twice before signing: what every buyer needs to know about property France

If you are tempted by a derelict farmhouse in Provence or a stone farmhouse outside Bordeaux, remember that renovating in France is different from renovating at home. Real estate France still draws buyers with charm and views, yet charm will not pay for underpinning or legal fees. In this article we unpack the practical mistakes buyers make, explain the legal rules that matter, and give a step-by-step checklist you can use before and after purchase.

I spoke with British architect Andrew Corpe of Andrew Corpe Architects, based in Luberon, Provence, whose practice has completed over 300 projects across France. His experience working on historic chateaux and new-build schemes highlights patterns that repeat across regions and price brackets. Below are the rules I would follow if I were buying a renovation project in France today.

Why renovating in France is not the same as renovating at home

French property law, planning control and construction practice have quirks that can catch buyers out. These are the realities:

• The cadastre is not a precise measurement tool. It often gives only approximate boundaries and distances.
• Local planning rules vary widely from one commune to the next but are enforced rigorously at the mairie and prefecture level.
• Mandatory insurance and contractor guarantees place legal responsibility squarely on the project team rather than on municipal inspectors.

From the outset, expect to involve a notaire, a géomètre (chartered surveyor), and usually a registered architect for larger projects. If you ignore those professionals, you are inviting cost and delay.

Eleven common mistakes and what they mean for your budget and timeline

Andrew Corpe lists 11 major aspects that routinely cause trouble. Below I set out each one, explain why it matters, and give practical steps to avoid it.

1) Orientation and sunlight

Why it matters: houses on the north side of a ridge lose winter sunlight and can feel damp and cold. Buyers often view properties in summer when light and warmth mask winter shortcomings.

What to do:

• Visit the property at different times of day and in winter if possible.
• Check the principal facade orientation; south or south-west is the preferred aspect for light and passive solar gain.

2) Land plot and boundaries

Why it matters: the cadastre in France is notoriously inaccurate. Easements and rights of way can run through gardens, and neighbours or the commune may claim ownership of outbuildings.

What to do:

• Insist on a survey from a géomètre before finalising the purchase.
• Check for easements, public roads, and rights of way.
• Verify the distance between the house and the boundaries because planning rules restrict extensions near boundaries.

Example from practice: Corpe has seen buyers discover an old public road behind their house and other cases where a neighbour or the commune claimed ownership of structures.

3) Planning regulations and zoning

Why it matters: zoning affects what you can convert, extend or demolish. In some areas conversion of agricultural buildings or additions are forbidden.

Key facts:

• Properties in agricultural zones (A) and natural zones (N) face strict limits on extensions and floor area.
• Construction of swimming pools is increasingly restricted in both urban and rural zones.
• If your project crosses thresholds or is within 500 metres of a protected monument you may need special permissions.

What to do:

• Ask the mairie for the local Plan Local d’Urbanisme (PLU) or the older POS documents.
• Use an architect to interpret the PLU and advise whether barns and non-habitable spaces can legally be converted.
• If a change of use or extension is required, insist on a planning decision before completing the purchase.

Practical risk: buyers have bought large farms only to learn that parts of the property were built illegally and cannot be regularised, blocking renovation plans.

4) Services: water, electricity, telecoms, drainage

Why it matters: service upgrades can be expensive and sometimes impossible if local networks lack capacity.

Common issues:

• Older properties may need electrical rewiring or upgrades to the connection point from the public network.
• Trenching to replace supply pipes or cables can add tens of thousands of euros.
• Septic systems (fosse septique) frequently fail to meet modern standards and nearly always require upgrading.
• Fibre and telephone may be unreliable; satellite services such as Starlink are often a fallback.

What to do:

• Ask for the current supply agreements and network capacity information from the mairie or utility companies.
• Include provisional costs for drainage and utility upgrades in your budget.

5) Diagnostic reports (les diagnostics)

Why it matters: French law requires sellers to produce a pack of diagnostic reports. These documents contain critical information that will shape the feasibility and cost of a renovation.

Essential documents to review:

• DPE (energy performance certificate) — a poor rating suggests major insulation and heating costs.
• Electrical safety report — rewiring is costly.
• Natural risks report — floods, earthquakes, clay soils and other hazards that can require major structural works.
• Asbestos, lead and termite reports — removal is expensive and adds no resale value.

Real example: Corpe refused a project for a house on clay soil with severe structural cracks; the buyer went ahead and now faces enormous underpinning costs.

What to do:

• Demand full copies of all legally required diagnostics before making an offer.
• Send them to your architect or a structural engineer for a quick technical opinion.

6) Underestimating renovation costs

Why it matters: enthusiasm, estate agent optimism and unknown defects make initial cost estimates unreliable.

Key cost drivers:

• Roof replacement
• Structural repair and underpinning
• Compliance upgrades to sanitation and electrics
• Insulation and heating systems to achieve regulatory standards

What to do:

• Obtain a preliminary cost estimate from an architect or quantity surveyor before making an offer.
• Build a realistic contingency into your budget; do not rely on verbal assurances from agents.

7) Ownership and title issues

Why it matters: buyers have discovered competing claims to buildings and plots, and in rare cases the commune owned a structure both parties claimed.

What to do:

• Use a notaire who represents only you, not the vendor. Never use the vendor’s notaire.
• Ask the notaire to check title deeds, historic actes and any previous registrations with the cadastre.

8) Obtaining planning permission before completion

Why it matters: if you need a change of use, an extension or approval for major works, a refusal after purchase leaves you stuck with a property you cannot legally adapt.

Key facts:

• A registered architect must submit a planning application if the total internal floor area exceeds 150 m².
• Vendors and agents sometimes resist delays to obtain permissions, but buying without them is risky.

What to do:

• If the project requires permission because of zoning, location or scale, insist on the planning decision prior to completion.
• Ask the notaire to include a contractual deadline for obtaining the permit.

9) Construction, guarantees and insurance

Why it matters: in France there is no routine inspection by district surveyors — responsibility rests with the project team.

Legal requirements:

• All professionals must carry insurance and provide a 10-year guarantee (garantie décennale).
• Owners must take out dommages-ouvrage (DO) insurance covering defects for 10 years and activating the contractors’ insurance automatically.

Common mistake: many owners skip DO insurance because there are no immediate checks; without DO you can be personally liable and resale can be impossible without it.

What to do:

• Request current insurance certificates from each contractor before work starts.
• If you employ an architect, they will usually manage these checks.

10) Contracts, payments and on-site control

Why it matters: casual agreements and cash payments lead to disputes, uninsured work and legal exposure.

Rules to follow:

• Each contractor must have a written contract with detailed costs, start and completion dates, penalties for delay, variation procedures, insurance details, and retention provisions.
• Never pay cash without an invoice showing VAT; it is illegal and leaves no protection.
• Record a formal handover with a snagging list at completion; this is essential for insurance claims.

11) Completion formalities and taxation

Why it matters: failing to declare works to the mairie and the tax office causes problems at resale and triggers backdated local taxes.

What to do:

• Notify the mairie on completion so they can verify compliance and issue the certificate needed for resale.
• Inform the tax office of improvements or extensions so the property tax and local taxes can be updated.

Budgeting, timelines and who to hire

A realistic budget and the right team are non-negotiable.