Certificate of Conformity: Can Your Neighbour Still Sue You?

Imagine: you have just built a 30 m² extension to your house in Tarnos. You obtained planning permission, complied with the rules, and even received the precious certificate of conformity (an official document certifying that your works comply with the planning permission). You thought you were safe, didn't you? But then your neighbour, unhappy with the obstructed view, sues you, arguing a breach of planning rules (local rules governing construction). "I have my certificate!" you exclaim. Yet, the French Supreme Court (the highest French court) has ruled: the certificate does not erase the fault. How is this possible? What does this decision mean for you? This article deciphers the judgment of 23 October 2013 (No. 12-24.919) and its practical consequences for owners, tenants and property professionals.

The facts: a story like many others

The case begins in Saint-Vincent-de-Tyrosse, in the Landes region. Mr Y. is the owner of a plot of land. In October 2001, he obtained planning permission for a detached house. Work was completed in March 2004. On 4 October 2004, the town hall issued a certificate of conformity (now called certificate of conformity of works). This document, issued after verification by the municipality, certifies that the construction carried out complies with the planning permission granted.

But Mr Y.'s neighbours see things differently. They consider that the construction violates the land use plan (POS, former name of the local development plan) and causes them damage (for example, loss of sunlight or an obstructed view). They sue Mr Y. on the basis of Article 1240 of the Civil Code (formerly Article 1382), which provides that "any act of a person which causes damage to another obliges the person by whose fault it occurred to make reparation". In short, they claim damages for breach of planning rules.

Mr Y. defends himself: "I have a certificate of conformity! It certifies that my works are legal. So you cannot say I committed a fault." The neighbours retort that the certificate does not prove compliance with planning rules, but only with the planning permission. However, the planning permission itself might have been granted in violation of the POS. The first instance court rules in their favour. Mr Y. appeals, then appeals to the Supreme Court. The Supreme Court dismisses his appeal by a judgment of 23 October 2013, confirming that the certificate of conformity does not erase the planning law fault.

The court's reasoning — analysed

The central question was: does the certificate of conformity prevent a neighbour from relying on a breach of planning rules to claim damages? The Supreme Court answers clearly: no.

Its reasoning is based on two ideas. First, the certificate of conformity has only an administrative scope (it certifies compliance with the planning permission for the purposes of the administration). It does not constitute a judicial recognition of the legality of the works with regard to all applicable rules. Second, the planning law fault (breach of a rule such as the POS) can be established by any means: bailiff's reports, photographs, witness statements, etc. The certificate is not irrefutable proof of the absence of fault.

In this case, the neighbours had demonstrated that the planning permission did not comply with the land occupancy coefficient (COS, former density indicator) provided for by the POS. Mr Y. had therefore committed a fault by building in breach of that rule, regardless of the certificate. The Supreme Court was here in line with its previous case law: it had already held that planning permission does not purge illegality (Cass. 3e civ., 15 Dec. 1993, No. 91-21.870). In other words, even a regular planning permission can be challenged if the final project does not comply with planning rules.

Note, however: the Court does not call into question the validity of the certificate itself. It distinguishes administrative legality (the certificate is valid) from civil liability (the owner may be ordered to compensate the neighbour). What few people know is that this decision is part of a broader movement to protect third parties against planning permissions.

What this changes for you — practically

If you are an owner-occupier or an individual who has carried out work, remember this: the certificate of conformity is not an absolute shield. Imagine that you built a swimming pool in Saint-Vincent-de-Tyrosse, compliant with the planning permission, but which encroaches on the minimum distance from the boundary (3 metres for example). Your neighbour can sue you under Article 1240, even if the town hall issued the certificate. The fault lies in the breach of the planning rule, not in the absence of a certificate.

For a tenant, this has little direct impact, but if you suffer damage (loss of view, overshadowing), you can take action against the landlord. For a buyer, this is a warning: before buying a property, it is prudent to check not only the planning permission and certificate, but also the actual compliance with planning rules. A notary or lawyer lawyer can help you.

In practice, courts may order the owner to pay damages ranging from a few thousand to several tens of thousands of euros, depending on the damage. For example, a loss of view of the mountains may be valued at €10,000. If you are in this situation, you must gather evidence of the breach (photographs, cadastral plan, POS) and consult a lawyer. The limitation period (time to sue) is 5 years from the discovery of the damage.

Four tips to avoid this type of dispute

• Check the PLU before any project: Consult the local development plan (PLU) of your municipality (available at the town hall or online) to know the applicable rules: height, distance, footprint, etc. In Tarnos, for example, the UD zone requires a setback of 4 metres from boundaries.
• Don't rely solely on the certificate: Even after obtaining the certificate, have the actual compliance verified by a professional (surveyor, architect) if your neighbour is litigious. An aerial photograph may reveal an overrun.
• Talk to your neighbours: Before building, inform your neighbours of your project. An amicable agreement (for example, compensation for loss of view) can avoid years of litigation. In Saint-Vincent-de-Tyrosse, an owner thus avoided a trial by offering a compensatory hedge.
• Insure your civil liability: Check that your home insurance policy covers damage caused to third parties in connection with building work. Some policies exclude planning disputes.
• Keep all your documents: Planning permission, certificate, plans, correspondence with the town hall. They may be useful in the event of a challenge.

Further reading: related case law and developments

This decision is part of a consistent line of the Supreme Court. As early as 1993 (Cass. 3e civ., 15 Dec. 1993, No. 91-21.870), it held that planning permission does not bar a liability action for breach of planning rules. More recently (Cass. 3e civ., 10 Mar. 2016, No. 14-27.223), it clarified that even a deemed planning permission (obtained without a response from the administration) does not prevent an action by neighbours. The trend is clear: the courts protect the rights of third parties against constructions, regardless of the administrative document obtained.

What this means for the future: caution is required. An owner cannot hide behind a certificate to ignore the rules. Professionals (developers, builders) must be extra vigilant in studying the PLU. Case law may evolve towards increased liability of municipalities in the event of wrongful issuance of the certificate, but that is not yet the case.

What you absolutely must remember

FAQ:

• Does my certificate of conformity protect me? No, it does not protect you against an action by your neighbour for breach of planning rules. The certificate certifies compliance with the planning permission, not legality under the PLU.
• What is the time limit to sue? The neighbour has 5 years from the discovery of the damage to sue you. This period can be long if the damage only appears later (cracks, etc.).
• Can I sue the town hall? Yes, if the certificate was issued illegally (for example, without verification). But this is rarer and more complex. Better to focus on the owner at fault.
• What if I am sued? Immediately consult a lawyer specialising in property law. Gather your documents and try mediation if possible.

Are you in a similar situation? A first 30-minute consultation with Maître Zakine (€45) can save you months of proceedings — and often much more. Book an appointment →