Co-ownership: what to do if a co-owner builds on the common plot?

Imagine: you inherit a plot of land with your two brothers and sisters in Lunel, near Montpellier. The land is held in co-ownership (shared ownership), each holding a share. One day, one of your brothers decides to build a garage on it without asking for your consent. What can you do? Wait for the partition of the co-ownership, which could take years? Or act immediately?

This is precisely the question put to the Court of Cassation in a case decided on 12 May 2010 (No. 09-65.362). The answer, clear and unambiguous: any co-owner can stop acts carried out by another co-owner that do not respect the intended use of the property or that infringe their equal rights in the co-owned thing. They can also claim damages (financial compensation) without waiting for the partition.

In other words, if a co-owner builds without agreement on the common plot, you are not obliged to suffer. You can take legal action to have the construction demolished and obtain compensation. This decision is fundamental for all co-owners, whether in Montpellier, Lunel or elsewhere in the south of France.

The facts: a story that happens every day

In this case, a plot of land was held in co-ownership between several persons. One of the co-owners, whom we shall call Mrs Z., had received a gift by notarial deed of 14 June 1966. This gift mentioned an area including part of the co-owned plot. In other words, she had received as a gift land that in reality encroached onto the common plot.

On this basis, Mrs Z. built a house on the part she believed to be hers, but which was in fact partly on the co-owned land. The other co-owners, unhappy, demanded the demolition of the structures (the building) and compensation for the damage suffered (the fact that the co-owned plot had become non-buildable because of the building).

The dispute was brought before the courts. At first instance, then on appeal, the judges had to decide: did Mrs Z. have the right to build? Could the other co-owners demand demolition without waiting for the partition? The case went up to the Court of Cassation, which delivered its judgment on 12 May 2010.

The reasoning of the court — dissected

The Court of Cassation relied on Article 815-9, paragraph 1, of the Civil Code, in its version prior to the Law of 23 June 2006. This text provides that any co-owner may use and enjoy the co-owned thing in accordance with its intended use. But it also states that a co-owner may stop the acts of another co-owner that do not respect this intended use or that infringe their equal rights.

In clear terms, each co-owner has an equal right in the property. If one of them acts as if they were the sole owner (for example by building without agreement), they violate the rights of the others. The latter can then ask the court to stop the infringement and even obtain damages (financial compensation) for the harm caused.

In this case, the Court considered that Mrs Z. had indeed erected structures on the co-owned plot, which constituted an infringement of the rights of the other co-owners. It did not matter that she had honestly believed the land belonged to her: the fact was that the building was partly on the common land. The other co-owners were therefore entitled to demand demolition and compensation.

What few people know is that this solution does not require waiting for the partition of the co-ownership. You can act immediately, as soon as the unauthorised act occurs. This is an essential protection for co-owners.

What this means for you — practically

If you are a co-owner (e.g. after an inheritance or a joint purchase), this decision gives you very concrete rights.

For the owner/landlord (co-owner): If a co-owner leases the common plot without your agreement, or builds a structure on it, you can take legal action to have the lease annulled or the demolition ordered. For example, in Montpellier, a co-owned plot leased for parking may generate a dispute if only one co-owner signs the lease. You could claim a share of the rents received and damages.

For the tenant: If you rent a co-owned property, you must check that all co-owners have agreed to the lease. Otherwise, the lease could be challenged. But rest assured: generally, the law protects the tenant in good faith.

For the buyer: Before buying a plot, make sure it is not in co-ownership with a neighbouring plot. A boundary survey (official delimitation) is essential. In Lunel, for example, a buyer discovered after the purchase that his land encroached onto the neighbour's plot: this led to lengthy litigation.

Indicative amount: If you obtain compensation for occupation without right, it may correspond to the rental value (rent) of the occupied land, multiplied by the duration of the occupation. For a 100 m² plot in Montpellier, this could amount to several thousand euros.

If you are in this situation, you should: 1) gather evidence (notarial deed, photos, bailiff's report), 2) consult a lawyer specialising in property law, 3) consider legal action without waiting for the partition.

Four tips to avoid this type of dispute

• Get a boundary survey done: Before any construction, have the exact boundaries of your land determined by a surveyor. This avoids encroachments onto neighbouring or co-owned plots. Cost: around €1,500 for a standard plot in Montpellier.
• Obtain written agreement from all co-owners: If you want to build on a co-owned plot, have all co-owners sign an authorisation. Better still: use a notarial deed to formalise the agreement.
• Prefer a co-ownership agreement: Sign an agreement that organises the management of the co-owned property: who can do what, how the fruits (rents, crops) are distributed, etc. This avoids conflicts.
• Act quickly in case of a dispute: As soon as you notice an unauthorised act, send a formal notice (registered letter with acknowledgement of receipt) to stop the works. If nothing is done, apply to the interim relief judge (urgent procedure) to obtain a quick decision.

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Further reading: related case law and developments

This decision is part of consistent case law. For example, the Court of Cassation had already ruled in 2004 (Civ. 1ère, 16 November 2004, No. 02-18.049) that a co-owner who builds without agreement on the common plot must demolish and compensate. The Law of 23 June 2006 then strengthened the rights of co-owners by providing that any administrative or disposal act requires unanimity (except for preservatory acts).

Trend: courts are increasingly strict towards co-owners who act alone. They consider that co-ownership is a temporary co-ownership that requires respect for everyone's rights. In the future, it is likely that judges will continue to protect co-owners against abuses.

What this means: if you are in a co-ownership, you have strong rights. But you must also exercise them promptly, because case law requires a reaction within a reasonable time.

Summary and next steps

FAQ:

1. Can I build on a co-owned plot without the agreement of the others? No, it is prohibited. You risk demolition and damages.
2. What to do if a co-owner builds without my agreement? Send a formal notice, then apply to the interim relief judge. You can claim demolition and compensation.
3. Do I have to wait for the partition to act? No, you can act immediately, as this judgment reminds us.
4. What are the time limits to act? In matters of encroachment, the action is in principle imprescriptible (no time limit). But to claim damages, you have 5 years from the date you became aware of the harm.
5. How much does a procedure cost? Count €2,000 to €5,000 in lawyer's fees, depending on complexity. Surveyor and bailiff costs are extra.

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