Building permit: lack of authorisation cannot be cured by illegality of refusal

Imagine: you own a flat in Beaulieu-sur-Mer, with a sea view. You decide to extend your terrace, but the town hall refuses the building permit. You consider this refusal unfair, even illegal. So you go ahead and build anyway, thinking that if the refusal is ever overturned, everything will be fine. Grave mistake. The Court of Cassation, in a judgment of 8 December 1976 (No. 75-90.921), ruled: even if the refusal of the permit is illegal, that does not justify building without authorisation. The offence remains punishable. This decision, still relevant today, reminds us of a golden rule: in planning law, prior authorisation is an absolute prerequisite. But what exactly does this change? And how should one react to a refusal considered abusive? Let's delve into the details.

The facts: a story that happens every day

In this case, a property owner had applied for a building permit to convert the attic of a building located in an urban area. The permit was granted, but subject to special conditions (technical requirements to be met). Unhappy with these conditions, he applied to modify the permit. The prefect refused this modification.

The owner then decided to proceed regardless: he carried out the work without complying with the conditions of the original permit. Prosecuted for an offence under the Urban Planning Code (construction without a valid permit), he attempted to defend himself by arguing that the refusal to modify the permit was illegal. According to him, if the refusal was illegal, then the conditions fell away, and he had the right to build as he wished.

The lower courts (criminal court, then court of appeal) convicted him. The owner appealed to the Court of Cassation. The Court of Cassation dismissed his appeal, upholding the conviction. In other words, even if the refusal to modify the permit was questionable, that did not make the construction lawful.

The reasoning of the court — broken down

The Court of Cassation relies on a fundamental principle: as soon as a structure is subject to a building permit, its construction cannot be undertaken until the authorisation has been obtained in its intended form. In other words, the permit must be valid and conform to the project. If the permit is refused (or granted with conditions that you dispute), you cannot build while waiting for the outcome of an appeal.

In short, the illegality of the refusal cannot compensate for the lack of authorisation. The unauthorised construction remains punishable, regardless of the legality of the refusal. The judges clarify that the offence is constituted by the mere fact of building without a valid permit. The legal basis is Article L. 480-4 of the Urban Planning Code (former Article L. 480-4), which penalises carrying out work without a permit or in violation of the permit's conditions.

This reasoning confirms earlier case law. It is a rule of common sense: if one could build by invoking the illegality of a refusal, that would open the door to unauthorised constructions under the pretext that the refusal is challengeable. However, this does not mean that the illegal refusal remains without consequence. The owner can still challenge the refusal before the administrative court and obtain its annulment. But that does not retroactively affect the criminal offence already committed.

What few people know is that this solution also applies to demolition permits or prior declarations. The principle is the same: authorisation must be obtained before acting.

What this means for you — concretely

This decision has very strong practical implications, whether you are a property owner, tenant, buyer, or co-owner.

• Landlord: If you want to raise your building in Nice to create an extra studio, and the town hall refuses the permit, do not start the work on the grounds that the refusal is absurd. You risk a fine (up to €120,000 for an individual, and up to €600,000 for a legal entity), an obligation to demolish, and even imprisonment (up to 6 months). Not to mention the impact on your insurance: a loss on an illegal construction may not be covered.
• Tenant: You are not directly concerned, but if your landlord carries out work without a permit, you could suffer nuisance or even eviction proceedings if the property becomes uninhabitable. Check that work undertaken in the building is authorised.
• Buyer: In Monaco as in Beaulieu-sur-Mer, before buying a property, ask the seller to provide the building permit for all visible modifications (conservatory, extension, change of use). If work has been done without a permit, you risk having to demolish it at your own expense, or being unable to insure it. undefined, I encountered a case where a buyer purchased a flat with a covered terrace without a permit: the town hall ordered demolition, and the seller did not compensate the buyer.
• Co-owner: In a co-ownership, private works affecting common parts (such as a roof opening) require not only a permit but also authorisation from the general meeting. Carrying out work without a permit exposes the co-ownership to proceedings, and the co-owner to having to restore the premises.

If you are in this situation, you must: 1) stop the work immediately, 2) consult a lawyer to regularise the situation (for example, by filing a new permit application complying with the conditions), and 3) not rely on the illegality of the refusal to justify yourself.

Four tips to avoid this type of dispute

• 1. Always obtain authorisation before starting: Never start work subject to a permit without having a valid and uncontested building permit in hand. If the permit has conditions, you must comply with them. If you challenge them, appeal, but do not start the work.
• 2. In case of refusal, use the appropriate appeal routes: Challenge a refusal of a permit before the administrative court (within two months of notification of the refusal). Do not build while waiting for the judge's decision. The appeal period is short, but the wait can be long (often 1 to 2 years). During that time, do not build.
• 3. Check the legality of works when purchasing: Before buying, ask the seller to provide all building permits and prior declarations for the work carried out. Use a notary or lawyer to verify compliance. If work is illegal, negotiate a price reduction or withdraw from the purchase.
• 4. In case of doubt, consult a lawyer before acting: A simple phone call can save months of proceedings. A 30-minute consultation with a lawyer specialised in property law can inform you about the feasibility of your project and the risks involved.

Further reading: related case law and developments

This 1976 decision is part of a consistent line of the Court of Cassation. For example, a judgment of 5 May 1992 (No. 90-86.051) recalls that the lack of a building permit is an instantaneous offence, completed as soon as the work is carried out, and that subsequently obtaining a regularisation permit does not erase the offence. Similarly, the Conseil d'État (administrative judge) considers that the illegality of a refusal of a permit cannot be invoked to justify construction without a permit (CE, 23 July 1974, No. 89920).

The trend of the courts is therefore very clear: prior authorisation is an absolute prerequisite. Even if the refusal is tainted with illegality, that does not confer a right to build. This rule is reinforced by recent reforms (the ALUR law of 2014, the ordinance of 2015) which have increased the police powers of mayors and criminal penalties. For the future, this case law can be expected to remain stable, as it guarantees legal certainty and public order in planning law.

Frequently asked questions

• Can I build if the refusal of the permit is manifestly illegal? No. Even if the refusal is illegal, you cannot build without a permit. You must challenge the refusal before the administrative court and wait for it to annul the refusal. Only after annulment can you file a new application or obtain a tacit permit.
• What if I have already built without a permit? Stop work immediately. Consult a lawyer to assess options: regularisation (if possible), or defence in case of prosecution. Do not try to justify your construction by the illegality of the refusal.
• What are the time limits for challenging a refusal of a permit? You have two months from notification of the refusal to apply to the administrative court. After this period, the refusal becomes final and you can no longer challenge it.
• What are the penalties for building without a permit? Fine of €1,200 to €120,000 (individual), up to €600,000 (legal entity), obligation to demolish or bring into compliance, and sometimes imprisonment (up to 6 months). The amount depends on the severity and the circumstances.
• Can a regularisation permit erase the offence? No, the offence is already constituted at the time of the work. The regularisation permit may avoid demolition, but does not prevent criminal prosecution. In practice, courts take regularisation into account to moderate the penalty.

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