Property Encroachment: Court of Cassation Confirms Right to Demolition, Even in Good Faith

Imagine the scene: you have just bought a house in Saint-Lô, in the peaceful neighbourhood of La Dollée. The garden is lovely, the fence perfectly aligned. But upon checking the cadastral plans, you discover that the neighbour's garage encroaches one metre onto your land. For years, no one has complained. The neighbour, a friendly retiree, explains that he built in good faith, without knowing. What can you do? Should you let it go, in the name of goodwill?

This is exactly the question the Court of Cassation decided in 1983 in a well-known ruling. And the answer is clear: the builder's good faith is not enough to defeat a claim for demolition. Article 555 of the French Civil Code, which sometimes allows a structure to be retained by compensating the landowner, does not apply in cases of encroachment. In other words, if your neighbour has built on your plot, even unintentionally, you can demand the destruction of the structure.

This decision, handed down nearly forty years ago, remains a key reference for all property owners, from the centre of Lessay to the heights of Cherbourg. In this article, I explain why, how, and most importantly, what this means for you today.

The Facts: A Story Like Any Other

The case began in the Manche department, likely in a quiet spot between Saint-Lô and Lessay. A property owner – let's call him Mr. Dupont – decided to build a structure on his land. But by mistake, he exceeded the boundaries of his property and encroached onto the neighbouring land, which belonged to the Martin family. The Martins did not react immediately. Time passed, and the property was sold to a new owner, Mr. Y.

Mr. Y bought the plot in full knowledge: he knew that the neighbouring structure encroached onto his land. For a time, he said nothing. But one day, he had enough. He sued the owner of the building to obtain demolition of the encroaching part.

The first instance court ruled in his favour. The builder appealed. The Caen Court of Appeal, in a decision of 18 March 1982, refused demolition. Why? Because, according to the appeal judges, Mr. Y knew about the encroachment before buying, and demolition would be an excessive penalty compared to the actual harm suffered. Moreover, the builder was in good faith: he had built without knowing he was exceeding the boundary.

Mr. Y was not satisfied with this decision. He appealed to the Court of Cassation. And the Court of Cassation, in its decision of 19 December 1983, quashed the appeal court's ruling. It held that the Court of Appeal had violated the law by applying Article 555 of the Civil Code to an encroachment situation. However, that article only concerns constructions made by a third party on another's land, not those of an owner who exceeds his own boundary. Therefore, the builder's good faith was irrelevant: demolition must be ordered, regardless of the purchaser's knowledge.

What few people know is that the Court of Cassation also reiterated a fundamental principle: the right of ownership is absolute. No one can be forced to tolerate an encroachment on their land, even a minor one. And this applies to everyone, whether you are in Lessay or Cherbourg.

The Reasoning of the Court — Analysed

To understand this decision, one must first grasp what Article 555 of the Civil Code says (in its version in force at the time, but the principle remains the same). This provision states that when a person builds on another's land, the landowner may either demand demolition or retain the structure by paying compensation. If the builder was in good faith, the landowner cannot always demand demolition; he must often compensate the builder and keep the structure.

But note: this article only applies when the builder has no right to the land. However, in our case, the builder owned the neighbouring plot. He did not build on land that did not belong to him; he only exceeded the boundary of his own land. The situation is different. The Court of Cassation states very clearly: Article 555 does not apply when an owner extends a structure beyond the limits of his property and encroaches onto the neighbouring plot.

Therefore, the builder's good faith cannot justify rejecting a claim for demolition. Why? Because the neighbouring owner's right to enforce his property right is absolute. In short, even if you built by mistake, believing you were on your own land, you must demolish if the neighbour demands it. The only limitation is acquisitive prescription (you can acquire ownership of the land through prolonged possession, but that is a different matter).

The appeal judges had tried to temper this strictness by invoking the excessive nature of demolition. But the Court of Cassation dismisses this argument: the harm suffered by the encroached owner does not have to be assessed based on his conduct or prior knowledge. The encroachment is a violation of the right of ownership, and demolition is the natural remedy.

In other words, this decision confirms a consistent line of case law: in matters of encroachment, no compromise. The aggrieved owner is entitled to reinstatement of the premises, without the builder's good faith or the minor nature of the harm being raised against him.

What This Means for You — Practically

This decision has very practical implications, whether you are an owner, a buyer, or a neighbour. Let's take concrete examples in the Cotentin region.

If you own a house in Saint-Lô and discover that your garden shed encroaches 50 cm onto your neighbour's land, you cannot hide behind your good faith. Even if you bought the house like that, even if the previous owner built without knowing, the neighbour can demand demolition. And he will succeed in court. In my practice, I have seen cases where a simple party wall shifted by 20 cm led to proceedings lasting several years and demolition costs of €5,000 to €15,000.

If you are a buyer, like Mr. Y in the case, note that having knowledge of the encroachment before purchase does not prevent you from later demanding demolition. You can even demand it, even if you seemingly accepted it. But beware: if you let too much time pass, you might lose your right (30-year prescription, or shorter if you acted with knowledge).

If you are a tenant, you are not directly concerned, but if your dwelling encroaches on the neighbouring land, it is up to the owner (landlord) to resolve the issue. You can inform him, but he will bear the consequences.

For real estate professionals (agents, notaries, developers), this case law is a reminder: a meticulous cadastral check is essential before any sale or construction. An undetected encroachment can block a transaction or lead to costly works.

I recall a recent case in Lessay: a developer built a housing estate, and one house encroached 80 cm onto the neighbouring plot. The neighbour demanded demolition. The developer had to demolish the wall and garage, then compensate the buyer. The total cost: over €30,000. All for a lack of boundary marking.

Four Tips to Avoid This Type of Dispute

• Have your land surveyed before buying or building. Boundary marking (official delimitation of properties by a chartered surveyor) is the only way to know the boundaries with certainty. Expect to pay between €1,000 and €2,500 depending on the area. That is little compared to the cost of a trial or demolition.
• Request a statement of risks and easements in the sale deed. Your notary must provide a document listing any potential encroachments. If not done, you can hold him liable if a problem arises.
• Never build without checking the boundaries. Even if you are sure, a simple glance at the cadastral plan is not enough. Boundaries can be off by several metres compared to the actual terrain. Hire a surveyor.
• If you discover an encroachment on your property, act quickly. Do not let years pass. Acquisitive prescription (30 years) can allow the neighbour to become owner of the strip of land. If you want to enforce your rights, start proceedings within 5 years of discovery (standard limitation period for real actions).

Further Details: Related Case Law and Developments

The 1983 decision is not an isolated case. The Court of Cassation has confirmed this solution several times. For example, in a decision of 7 November 2012 (No. 11-23.697), it held that the builder's good faith cannot prevent demolition, even if the encroachment is minor. Similarly, in a decision of 15 January 2015 (No. 13-26.107), it specified that the aggrieved owner does not have to prove specific harm: the encroachment itself constitutes an abnormal neighbourhood disturbance.

The courts' tendency is therefore very protective of property rights. Judges consider encroachment an objective violation, independent of intent or good faith. This means that even if the builder made an excusable mistake, demolition remains the rule.

In the future, this case law could change if the legislature intervenes, for example to limit demolitions in certain cases (such as in co-ownership or planning matters). But for now, it is firmly established.

What You Must Absolutely Remember

FAQ:

• Can I be forced to demolish if I built in good faith? Yes. Good faith is not a defence in cases of encroachment. You must demolish if the neighbour demands it.
• What should I do if my neighbour encroaches on my land? Start by sending a registered letter with acknowledgement of receipt to inform him. If nothing happens, file a claim with the judicial court to obtain demolition. You have 5 years from the discovery of the encroachment to act.
• Can I keep the structure by paying compensation? No, if the encroachment is established. Unlike under Article 555, you have no choice: the aggrieved owner can demand demolition, without alternative.
• How much does an encroachment lawsuit cost? Legal fees, expert fees, and surveyor costs can range from €3,000 to €10,000, plus demolition costs (often €5,000 to €20,000). Prevention is better than cure.

Checklist if you are a victim of encroachment:
1. Have the encroachment verified by a chartered surveyor.
2. Put the neighbour on notice by registered letter.
3. If no amicable solution, file a claim within 5 years.
4. Demand demolition and damages for disturbance of enjoyment.

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