Town Planning: When the Court Orders the Demolition of Your Illegal Construction

Imagine you are a property owner in Biscarrosse. You have bought a plot of land with a magnificent view of the lake, and you dream of building a conservatory there to enjoy the Landes sunshine. You start the works without asking too many questions, convinced that your project is reasonable. But a few months later, you receive a registered letter from the town hall: your construction is illegal, and you are asked to demolish it. Panic ensues! What to do? Can you challenge this decision? And if the administration does not appear in court, does that change anything?

This is exactly the type of situation that the Court of Cassation ruled on in this 1986 decision. A judgment that, nearly forty years later, remains highly relevant for anyone considering works without planning permission. Because yes, town planning rules are not mere administrative formalities: they can lead to costly demolitions and endless legal proceedings.

In this article, I will explain in plain language what this decision says, why it is important for you, and above all how to avoid finding yourself in this situation. Because in matters of town planning, prevention is better than cure – especially when the "cure" can cost several tens of thousands of euros.

The facts: a story that happens every day

Let's go back to 1986. Mr. Dupont (fictitious name) is the owner of a plot of land in La Croix-Valmer, in the Var department. Like many property owners, he has plans for his property. He decides to build a structure on his land, without applying for the required prior authorisation. A classic mistake, which I regularly observe in my practice, particularly in the jurisdiction of Mont-de-Marsan where some property owners think they can "do as they please" on their land.

The Prefect of Var, alerted to this illegal construction, initiates legal action. He asks the court to convict Mr. Dupont for an infringement of the Town Planning Code and, above all, to order the bringing into compliance or demolition of the structure. At first instance, the judges rule in favour of the Prefect and order the demolition. Mr. Dupont, dissatisfied, appeals.

And this is where things become interesting. During the appeal hearing, the Prefect – although a party to the proceedings – does not appear. He does not attend. Only the Advocate General (the representative of the public prosecutor's office) submits submissions, referring to the observations presented at first instance by the competent official of the Departmental Equipment Directorate (the administration responsible for town planning at the time).

Mr. Dupont perhaps thinks he has found a loophole: if the administration does not appear, maybe the Court of Appeal will reject the demolition request? Mistake. The Court of Appeal confirms the first instance judgment and maintains the demolition order. Mr. Dupont then appeals to the Court of Cassation, but the Court of Cassation dismisses his appeal. The story ends badly for him: his illegal construction will have to be demolished, with all that this implies in terms of costs and loss of value.

The court's reasoning – dissected

But why did the Court of Appeal confirm the demolition when the Prefect had not appeared at the hearing? This is where the judges' reasoning is important to understand.

The Court of Cassation first recalls the legal basis: Articles L. 480-5 and L. 480-6 of the Town Planning Code (the texts governing sanctions for infringements of town planning rules). These articles provide that in the event of a conviction for infringement of town planning rules, the judges must rule on the bringing into compliance of the structures or on their demolition. And they must do so "in light of the written observations or after hearing the competent official".

In other words, the law does not say that the administration MUST be present at the hearing. It says that the judges must make their decision taking into account the observations of the administration – whether these observations are presented orally during a hearing, or in writing. In this case, the competent official had presented written observations at first instance, and the Advocate General had referred to them on appeal. That was sufficient.

The Court of Cassation therefore applies the law strictly: "Makes an exact application of Articles L. 480-5 and L. 480-6 of the Town Planning Code". It reminds us that the absence of the Prefect at the appeal hearing does not deprive the judges of the power to rule on the demolition, provided that they have been able to take note of the administration's observations by other means (here, the submissions of the Advocate General which reproduced the official's observations).

What few people know is that this decision is part of a consistent line of case law: judges have discretionary power to order the demolition of an illegal construction, and this power does not depend on the physical presence of the administration at the hearing. What matters is that the file is complete and that the judges have all the elements to make their decision.

What this means for you – concretely

But what exactly does this change for you, as a property owner, tenant, or real estate professional? Much more than you think.

If you are a property owner and have carried out works without authorisation, this decision means that you cannot rely on a possible absence of the administration in court to escape a conviction. Even if the representative of the town hall or prefecture does not appear at the hearing, the judges can still order the demolition of your construction, based on the written file. undefined, I have encountered cases where property owners in Saint-Paul-lès-Dax had built garden sheds or extensions without planning permission, thinking that "no one would check". Serious mistake: today, with satellite photos and neighbours' reports, checks are increasingly frequent.

If you are a purchaser of a property, this decision reminds you of the importance of checking the town planning compliance of the property before buying. Because if you buy a house with an illegal conservatory, it is YOU who will have to demolish it – even if it was the former owner who built it. The costs can be considerable: for a 50 m² construction, demolition can easily exceed €10,000, not counting the loss of value of the property.

If you are a tenant, know that your landlord cannot force you to live in non-compliant accommodation. If illegal works have been carried out in the property you rent, you can demand their regularisation or demolition – and if the landlord refuses, you can take the matter to court.

In short, this decision reinforces the principle that town planning rules are mandatory. They cannot be circumvented, and judges have the means to enforce these rules, even when the administration is not physically present in court.

Four tips to avoid this type of dispute

• Always apply for planning permission or a prior declaration before starting works. Even for a small construction like a garden shed or a fence. In Biscarrosse as elsewhere, town planning rules are strict, and checks are frequent.
• Consult the PLU (Local Town Plan) of your municipality before buying land or planning works. The PLU determines what you can build, where, and under what conditions. In Saint-Paul-lès-Dax, for example, some areas are classified as "natural" and prohibit any new construction.
• Have the town planning compliance checked by a professional (architect, chartered surveyor, specialised lawyer) before buying a property. A town planning certificate does not guarantee that existing constructions are legal.
• Do not rely on limitation periods to regularise an illegal construction. Contrary to a common misconception, an illegal construction does not become legal over time. Only a regularisation procedure (possibly with a fine) can make it compliant.

Further reading: related case law and developments

This 1986 decision is part of a consistent line of case law from the Court of Cassation. Already in the 1970s, the high court reminded us that the lower courts (tribunals and courts of appeal) have discretionary power to order the demolition of an illegal construction, and that this power does not depend on the presence of the administration at the hearing.

More recently, in a judgment of 13 March 2019 (No. 17-27.223), the Court of Cassation confirmed this position by specifying that judges can order demolition even when the illegal construction is old and integrated into the environment. The trend is clear: courts are increasingly severe with illegal constructions, especially in protected areas (coastal areas, natural parks, etc.).

What does this mean for the future? That checks will intensify, particularly with the use of drones and satellite photos. And that judges will continue to order demolitions, even for constructions that seem "minor". In the jurisdiction of Mont-de-Marsan, I have seen cases where swimming pools or terraces had to be demolished because they encroached on a non-buildable zone.

Checklist before acting

• Before buying land: consult the PLU, check the easements, request an operational town planning certificate.
• Before starting works: submit an authorisation application (planning permission or prior declaration) and wait for the town hall's approval before starting.
• If you have already built without authorisation: do not delay in consulting a specialised lawyer to assess the risks and, if possible, initiate a regularisation procedure.
• If you receive a formal notice from the town hall: react quickly. Ignoring a formal notice worsens the situation and can lead to legal proceedings with a demolition order.
• If you are a tenant in non-compliant accommodation: demand regularisation from your landlord, and if necessary, refer the matter to the departmental conciliation commission or the court.

Do you find yourself 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 →