Violation of the PLU: the interim relief judge can order demolition at the owner's expense

Imagine the scene: you are the owner of a pretty house in Aix-les-Bains, with a view of the lake. To gain a little space, you decide to build a small extension without checking the local urban development plan (PLU). A few months later, the town hall serves you with a formal notice to demolish, then applies to the interim relief judge. You thought that court proceedings would take years? Think again. The Court of Cassation has just handed down a decision that changes the situation.

This case raises a crucial question: how far can the interim relief judge go to stop a violation of the PLU? Can he order reinstatement and authorise the municipality to act at the owner's expense, without waiting for a trial on the merits? The answer is yes, and that is the whole point of the judgment of 27 March 2025 (no. 22-12.787).

But beware: this decision does not only concern big developers. It affects any owner who carries out unauthorised works, in Aix-les-Bains as in Cognin. So, what exactly does the Court of Cassation say? And above all, how can you avoid finding yourself in this situation?

The facts: a story that happens every day

Mr X is the owner of a plot of land located in Aix-les-Bains, in zone UB of the PLU. Without worrying about planning rules, he carries out construction work on a residential building, without a building permit. The town hall of Aix-les-Bains, alerted by a neighbour, notes the breach and sends a letter of formal notice. To no avail: Mr X continues his work.

The municipality then decides to apply to the interim relief judge of the Chambéry judicial court on the basis of Article 835 of the Code of Civil Procedure, which allows the judge to order interim measures in cases of urgency or manifestly unlawful disturbance. The judge finds that the construction violates the provisions of the PLU (height, footprint, use) and constitutes a manifestly unlawful disturbance. He orders Mr X to restore the premises within six months, and specifies that, failing execution, the municipality may proceed with demolition works at the owner's expense.

Mr X appeals. The Chambéry Court of Appeal upholds the order. He then appeals to the Court of Cassation, arguing that the interim relief judge cannot, in his view, authorise the municipality to act at his expense. The Court of Cassation dismisses his appeal and upholds the decision.

The reasoning of the court — dissected

The Court of Cassation relies on two essential texts. First, Article 835 of the Code of Civil Procedure, which allows the interim relief judge to order all necessary measures to stop a manifestly unlawful disturbance. Second, Article L. 480-14 of the Urban Development Code, which provides that the municipality may ask the civil judge (not only the criminal judge) to order the demolition of a structure built without authorisation. The Court adds that the interim relief judge may attach to this injunction a clause authorising the municipality to carry out the works at the owner's expense, without exceeding his powers.

In clear terms, the Court of Cassation considers that the general interest attached to compliance with planning rules justifies swift action. The interim relief judge, competent for urgent matters, may therefore order reinstatement and provide for enforced execution if the owner does not comply with the injunction.

What few people know is that this decision confirms already well-established case law. The Court of Cassation had already held, in a judgment of 13 January 2021 (no. 19-22.504), that the interim relief judge could order the demolition of an unlawful structure. But here, it goes further by specifying that the municipality may be authorised to act on its own. This is an important development for local authorities.

Mr X's arguments? He argued that only the criminal judge could order such a measure, and that the interim procedure did not allow anticipating a debate on the merits. The Court rejects this argument: the manifestly unlawful disturbance is obvious (violation of the PLU), so the interim relief judge can intervene without waiting.

What this changes for you — concretely

If you are an owner (landlord or occupant) and you are planning works, first check the PLU of your municipality. A simple extension without a permit can cost you dearly. Let's take an example: in Cognin, an owner builds a 20 m² conservatory without prior declaration. The town hall notes the excess footprint. The interim relief judge orders demolition. The owner does nothing. The municipality hires a company to demolish and sends him the bill: €15,000 for works, plus €3,000 in legal fees. All in less than a year.

Another consequence: if you are a buyer of a property, check that existing structures comply with the PLU. Non-compliance may be enforceable against you, and you could be forced to demolish at your own expense, even if you did not carry out the works.

If you are a tenant, know that the procedure targets the owner, but you may be evicted if the property must be demolished. In practice, the judge may impose rehousing at the owner's expense.

Finally, for co-owners, be careful with private works that affect the common parts or the external appearance: they may also be sanctioned by interim relief proceedings.

Four tips to avoid this type of dispute

• Consult the PLU before any project. Go to the town hall or the website of your municipality. Check the rules on height, footprint, use. In Aix-les-Bains, the PLU is particularly strict in the area near the lake.
• Submit the necessary authorisations. Building permit, prior declaration: do not neglect them. Even for a small extension, a declaration is often mandatory.
• If in doubt, seek legal advice. Maître Zakine can advise you before starting works. A 30-minute consultation (€45) can save you thousands of euros in demolition costs.
• If you receive a formal notice, do not ignore it. Respond, request a deadline, or better, regularise your situation if possible. Inaction can lead to interim relief proceedings and additional costs.

Besoin d'un conseil personnalisé ? Contactez Maître Zakine — première consultation 30 min à 45€.

Further reading: related case law and developments

This decision is part of a broader trend of courts strengthening the effectiveness of municipalities' actions in planning matters. Already, in a judgment of 10 September 2020 (no. 19-16.567), the Court of Cassation had held that the interim relief judge could order the demolition of a structure built without a permit, on the basis of Article 835. The 2025 judgment goes further by specifying the possibility of authorising enforcement by the municipality.

However, some Courts of Appeal had been more restrictive, considering that demolition fell solely within the jurisdiction of the trial judge. The Court of Cassation puts an end to these divergences. Henceforth, the interim relief route is clearly open.

For the future, it is expected that municipalities will increasingly use this fast and effective procedure. Owners will therefore have to be extra vigilant.

What you absolutely must remember

Practical FAQ:

1. Can the interim relief judge really order demolition? Yes, if the construction violates the PLU and constitutes a manifestly unlawful disturbance.

2. Can I challenge the order? Yes, by appeal within 15 days. But if the disturbance is obvious, your chances of success are limited.

3. What are the timeframes? Allow 3 to 6 months to obtain an interim relief order, then a 6-month period to demolish. After this period, the municipality may act.

4. How much does it cost? Demolition costs are borne by you, as well as the municipality's legal fees. Expect at least €10,000 for a small structure.

5. Can I regularise after the fact? Sometimes, if the PLU allows it (e.g., amendment of the regulations). But this is rare. Better to prevent.

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 →