Construction on Another's Land: When Authorisation is Not Enough to Be in Good Faith

Imagine for a moment: you are the owner of a villa in Cannes, with a beautiful sea view. Your neighbour, Mr Dupont, asks your permission to build a small annexe on a plot adjacent to yours, on the boundary line. You agree, orally, without any written formalities. The works progress, the annexe is almost finished. But a dispute arises over the boundaries of the land, and you realise that the annexe actually encroaches on your property. What happens? Can you demand demolition? And can your neighbour rely on your authorisation to avoid demolishing everything? This crucial question was decided by the Court of Cassation in a judgment of 15 April 2021 (appeal no. 20-13.649).

Good faith, within the meaning of Article 555 of the Civil Code (which governs constructions on another's land), is not simply assessed by the owner's consent. It requires that the builder possesses as owner by virtue of a title transferring ownership (a sale deed, a gift, etc.) whose defects he is unaware of. In other words, to be considered a builder in good faith, it is not enough to have the owner's authorisation; you must also have a title that leads you to believe you are the owner of the land. This distinction is fundamental, because it determines whether you can be forced to demolish at your own expense or whether you can obtain compensation.

In this case, an individual had built on the land of a certain Mrs Y. with her authorisation, but without a title deed. The Court of Appeal ordered the demolition of the building at the builder's expense, and the Court of Cassation upheld this decision. It held that the builder, not being in good faith (in the legal sense), could not invoke a waiver by the owner of his right to demand demolition. In clear terms, even if the owner said 'yes' initially, he can change his mind and demand the reinstatement of the premises. This decision is a reminder for all those who build without ensuring their right of ownership.

The Facts: A Story Like Many That Happen Every Day

Mr X, an individual, was authorised by Mrs Y., owner of a plot of land in Cannes, to build a building on it. The owner gave her verbal consent, and the works were carried out. But later, a conflict arose: Mrs Y. demanded the demolition of the building, considering that the construction was irregular and that it interfered with her project. Mr X, for his part, argued that Mrs Y.'s authorisation amounted to a waiver of her right to demand demolition, and that he was in good faith. He therefore refused to demolish.

The case was brought before the Grasse Judicial Court, then before the Aix-en-Provence Court of Appeal. The lower courts ruled in favour of Mrs Y., ordering demolition at Mr X's expense. The latter appealed to the Court of Cassation, arguing that the Court of Appeal should have investigated whether Mrs Y. had not waived her right to demand demolition by authorising the works. The Court of Cassation dismissed this appeal, confirming that Mr X was not in good faith and that the demolition was justified.

The twist? The Court of Cassation held that the question of waiver was inoperative (without effect) since Mr X was not a builder in good faith. Indeed, Article 555 of the Civil Code distinguishes two situations: if the builder is in good faith, the owner can only demand demolition if he compensates the builder; if the builder is in bad faith, the owner can demand demolition without compensation, or keep the construction by paying a lower compensation. Here, Mr X being in bad faith (because without a title deed), Mrs Y. had the choice between demolition and repurchase.

The Reasoning of the Court — Analysed

To understand the judgment, we must first read Article 555 of the Civil Code, which provides: "When plantations, constructions and works have been made by an evicted third party, the owner of the land may, at his option, keep the ownership or demand their removal." This text distinguishes according to the good faith of the builder. But what is good faith? Article 550 of the same code specifies: "Possession is in good faith when the possessor believes, by a just title, to be the owner of the thing he possesses." In other words, to be a builder in good faith, you must possess the land by virtue of a title (a sale deed, for example) that leads you to believe you are the owner, and be unaware of the defects of that title.

In our case, Mr X held no title of ownership to Mrs Y.'s land. He only had an oral authorisation to build. This authorisation did not confer on him the status of owner, nor even of possessor as owner. He was therefore not in good faith within the meaning of Articles 555 and 550. The Court of Appeal correctly deduced from this finding that Mr X was in bad faith, and that Mrs Y. could demand demolition without having to prove a waiver.

What few people know is that the notion of "good faith" in property law is very technical. It is not a mere subjective belief; it is framed by texts. The Court of Cassation here reminds us that an authorisation to build, even express, does not amount to a title of ownership. Thus, even if you have the owner's consent, if you build on his land without being yourself the owner (or without a title leading you to believe you are), you are considered a builder in bad faith. This interpretation has been consistent for a long time, and the 2021 judgment is not a reversal but a confirmation.

Mr X's arguments were nonetheless tempting: "I was authorised, so I thought I had the right to build." But the Court of Cassation swept this argument aside: without a title, no good faith. However, note: if Mr X had bought the land from Mrs Y. by a void sale deed (for example, for a grossly inadequate price), and he was unaware of this defect, he could have been considered in good faith. But that was not the case.

What This Means for You — Concretely

This decision has important practical implications for several profiles. If you are a landowner, you can authorise someone to build on it, but you can also change your mind and demand demolition, without having to compensate the builder, provided that the builder has no title of ownership. This is a powerful weapon: you retain control over your property. But be careful: if you allow building without protesting for a long time, you could be considered to have tacitly waived your right to demand demolition (by the effect of acquisitive prescription or waiver). In our case, the Court of Cassation specified that in the absence of good faith of the builder, the question of waiver did not even arise.

For a tenant or an occupant without title, this case law is a warning: even with the owner's verbal consent, any construction you carry out on his land can be demolished at your expense. Do not rely on a mere oral authorisation. In Le Cannet, for example, a tenant had built a veranda with the owner's consent, but without a building permit. The owner later demanded demolition, and the tenant had to pay €15,000 for demolition works. He had no recourse, because he was not the owner of the land.

For a purchaser, this decision reminds us of the importance of checking the title deed before undertaking works. If you buy a plot and build before the signing of the notarial deed (for example, on the basis of a promise of sale), you are not yet the owner. If the sale falls through, you could be considered a builder in bad faith. undefined, I have encountered cases where purchasers started works after signing the promise but before the final deed. The sale was cancelled, and they had to demolish at their own expense. A dead loss of several tens of thousands of euros.

Four Tips to Avoid This Type of Dispute

• Never build without a title of ownership. Before building on land, ensure you are the owner or hold a valid title (sale deed, gift, etc.). A mere verbal or written authorisation from the owner is not enough.
• Require a precise written document. If the owner authorises you to build, have a written agreement drafted specifying the limits of the authorisation, the duration, and the consequences in case of dispute. Ideally, establish a right of superficies or an easement.
• Check the boundaries of the land. Hire a chartered surveyor to precisely demarcate your property before any construction. Even a minor encroachment can lead to demolition.
• Take out latent defects insurance and public liability insurance. If you are a builder, this insurance will cover any potential defects or damage. But it will not protect you against an action for demolition based on the lack of title.

Further Analysis: Related Case Law and Developments

This decision is part of a consistent line of authority from the Court of Cassation. Already in 2015 (Civ. 3e, 10 March 2015, no. 13-27.202), the Court had held that the builder's good faith presupposes that he possesses as owner by virtue of a title whose defects he is unaware of. The 2021 judgment merely confirms this position. On the other hand, a more recent decision (Civ. 3e, 9 February 2022, no. 20-23.110) specified that even in the absence of a title, the builder may be in good faith if he legitimately believed he was the owner due to an erroneous notarial deed (for example, an inaccurate boundary survey). But in that case, he must demonstrate this legitimate belief.

The trend of the courts is therefore to protect the landowner, unless the builder can rely on an apparent title. This case law is stable, and it is unlikely to evolve in a direction more favourable to builders without title. For the future, it is advisable for owners to monitor constructions on their land and react quickly, because silence could be interpreted as a tacit waiver after a certain period (30 years for acquisitive prescription, but waiver may occur more quickly in case of positive acts).

Summary and Next Steps

FAQ:

• Q: Can I build on my neighbour's land if he authorises me? A: Yes, but you do so at your own risk: the owner can at any time demand demolition, unless you have a title of ownership.
• Q: How can I be considered a builder in good faith? A: You must possess the land by virtue of a title transferring ownership (sale deed, gift) and be unaware of the defects of that title.
• Q: What should I do if I have already built without a title? A: Try to regularise your situation: either by acquiring the land (by sale), or by obtaining a right of superficies. Consult a lawyer to negotiate with the owner.
• Q: What are the time limits for action? A: The owner can bring an action for demolition as long as prescription has not been acquired (30 years). But if you built with his consent, it may be more difficult for him to act after a long silence.

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