Right to Build in Co-Ownership: When the Regulations Prevail Over Co-Owners' Authorisation

Imagine you own a plot of land in Tarnos, in the residential district of La Barre. You have purchased a co-ownership lot (a property divided into several parts belonging to different owners) with an unbuilt space, and you dream of building an extension to enlarge your house. But here's the catch: your neighbour, also a co-owner, objects, believing that you must obtain the agreement of the general meeting of co-owners. Who is right?

This situation, common in co-ownerships in the Landes region like in Mont-de-Marsan or on the Côte d'Azur, raises a fundamental question: is the right to build always subject to the authorisation of the other co-owners? The answer is not as simple as one might think, and it often depends on a document too often overlooked: the co-ownership regulations.

A decision of the Cour de cassation (the highest French judicial court) of 8 June 2011 provides crucial insight on this point. It confirms that, in certain cases, the holder of a transitional lot (a lot intended to be built later) can escape the usual authorisation rules. But what does this change concretely for you?

The Facts: A Story as It Happens Every Day

The story begins in a co-ownership in Poitou, but it could have taken place in Mont-de-Marsan, in the Nonères district, or in Tarnos near Lac de la Barre. Mr and Mrs Martin (fictitious names for the example) are owners of several lots in a co-ownership. Among these lots, they hold a so-called "transitional" lot—that is, a space not yet built, intended to accommodate future constructions.

The Martins decide to build on this transitional lot. They have a specific project: to erect an additional building and create new co-ownership lots that they can sell separately. But here's the issue: other co-owners oppose this project. They believe that any new construction in co-ownership must be authorised by the general meeting of co-owners, in accordance with the usual rules of co-ownership.

The conflict escalates. The opposing co-owners take legal action, requesting a halt to the works. They invoke the principle that works affecting the common parts (elements shared by all co-owners, such as roofs, staircases, foundations) require the agreement of the majority of co-owners. For them, building on a transitional lot necessarily affects the entire co-ownership.

The Martins, for their part, brandish their co-ownership regulations. They assert that this document, signed by all co-owners originally, explicitly grants them "the right to erect all buildings and constructions" on their transitional lot. According to them, this right is inherent to their ownership and does not have to be subject to the authorisation of others.

The case goes before the court of first instance, then before the Court of Appeal of Poitiers. The appeal judges rule in favour of the Martins on 31 March 2010. The opposing co-owners do not give up and file an appeal (a recourse) before the Cour de cassation. It is this latter decision, rendered on 8 June 2011, that sets a precedent.

The Court's Reasoning—Analysed

The Cour de cassation dismisses the appeal of the opposing co-owners and confirms the Court of Appeal's ruling. Its reasoning rests on a fundamental distinction between two types of rules: those stemming from the law, and those stemming from the co-ownership regulations.

Under French law, co-ownership is governed by the law of 10 July 1965, codified in Articles 641-1 et seq. of the Civil Code. This law indeed provides that works affecting the common parts require authorisation from the general meeting. This is what is called the principle of unanimity or majority depending on the nature of the works.

But be careful: the Cour de cassation reminds that the co-ownership regulations, when clear and precise, can derogate from certain general rules. In other words, what the co-owners accepted by signing the regulations prevails over supplementary legal provisions (those that apply only if the parties have not provided otherwise).

In this case, the magistrates examine the co-ownership regulations carefully. They note that it contains a specific provision concerning the transitional lot: its holder benefits from the "right to erect all buildings and constructions". This wording is crucial. It means that the right to build is an integral part of the rights attached to this particular lot.

The Court deduces that, in this specific case, the holder of the transitional lot does not need the authorisation of the other co-owners to exercise their right to build. Why? Because this right was expressly provided for and accepted by all when the regulations were established. The opposing co-owners cannot therefore go back on what they initially accepted.

What few people know: this decision does not create an absolute right to build without limits. It simply specifies that when the co-ownership regulations explicitly grant a right to build on a transitional lot, this right can be exercised without the additional authorisation of the general meeting. But this does not exempt the builder from obtaining the usual administrative authorisations (building permits, prior declarations) nor from respecting planning rules.

In short, the Cour de cassation makes a subtle but essential distinction: it separates the right to build (which can be provided for by the regulations) from the practical exercise of this right (which remains subject to planning rules and administrative authorisations).

What This Changes for You—Concretely

But what exactly does this change in your life as an owner, tenant, or real estate professional? The implications are significant and vary depending on your situation.

If you are the owner of a transitional lot: this decision gives you a valuable legal weapon. Before undertaking works, examine your co-ownership regulations meticulously. If it contains a clause similar to that in the Martin case, you will probably be able to build without the agreement of the other co-owners. undefined, I have encountered cases where owners in Mont-de-Marsan were thus able to increase the value of their property by 30 to 50% by building a legal extension. But be careful: check first with a professional, as each set of regulations is unique.

If you are a co-owner in a building containing a transitional lot: be vigilant. When purchasing, read the regulations carefully. If it grants special rights to the holder of the transitional lot, you will probably not be able to oppose their future construction projects. This can affect your quality of life (noise, overlooking, occupation of common parts during works) and the value of your own lot.

If you are a tenant in a co-ownership with a transitional lot: construction works may be undertaken without your landlord necessarily having a say. This can mean temporary nuisances. Check your lease: some clauses provide for rent reductions in case of abnormal disturbances of enjoyment.

If you are a real estate professional (agent, developer, notary): this decision changes the game for valuing transitional lots. A lot with a building right guaranteed by the regulations is worth more than a lot subject to co-owners' authorisation. During transactions, insist that the regulations be examined by a specialised lawyer. An oversight can be costly: I have seen projects blocked for months, with legal fees exceeding €10,000, because the regulations had not been properly analysed.

For potential purchasers: before buying a transitional lot, request a legal analysis of the regulations. The purchase price should reflect the reality of the rights attached to the lot. A lot with a certain building right justifies a premium compared to a lot whose building right is uncertain.

Four Tips to Avoid This Type of Dispute

• Read your co-ownership regulations before buying or selling: do not rely on verbal promises. Only the written document is binding. Have it reviewed by a professional if necessary.
• Have a joint inspection report of the common parts drawn up: before undertaking works on a transitional lot, document the initial state of the common parts with photos and videos. This will avoid later disputes over potential damages.
• Consult a specialised lawyer before embarking on major works: one hour of consultation (approximately €150-250) can save you years of proceedings and tens of thousands of euros in fees.
• Anticipate administrative authorisations: even if the regulations give you the right to build, you will need to obtain a building permit or a prior declaration. Inquire at your town hall about applicable planning rules, especially in protected areas like certain districts of Tarnos.

Besoin d'un conseil personnalisé ? Contactez Maître Zakine — première consultation 30 min à 45€.

In-Depth Analysis: Related Case Law and Developments

The 2011 decision is part of a broader body of case law. Already in 2006, the Cour de cassation had rendered a similar ruling (Cass. 3e civ., 15 March 2006, no. 04-20.223) confirming that co-ownership regulations could attribute specific rights to certain lots. This trend is strengthening: courts increasingly recognise the contractual freedom of co-owners in drafting their regulations.

However, there are limits. In 2018, the Cour de cassation (Cass. 3e civ., 12 July 2018, no. 17-19.131) reminded that co-ownership regulations cannot contravene public policy. For example, it could not authorise constructions contrary to safety or hygiene rules.

What does this mean for the future? Co-ownership regulations will take on increasing importance. Co-owners will need to be particularly attentive to their drafting, especially when creating new co-ownerships. Property developers might be tempted to include clauses favourable to the lots they retain for later construction. How to react? By being vigilant and seeking independent advice.

Checklist Before Acting

If you are the owner of a transitional lot and wish to build:

1. Consult your co-ownership regulations: does it contain a specific clause on the right to build?
2. Have this clause analysed by a lawyer specialised in property law.
3. Check planning rules with your town hall: is your project authorised?
4. Prepare a complete file for the building permit or prior declaration.
5. Inform your neighbour co-owners of your project, even if their agreement is not required: this preserves neighbourly relations.

If you are considering purchasing a transitional lot:

1. Request a copy of the co-ownership regulations before signing the preliminary agreement.
2. Have a professional verify if the lot benefits from a certain building right.
3. Assess the real construction potential: is the land buildable? Are there any easements (rights in favour of another plot)?
4. Negotiate the price based on the real rights attached to the lot.
5. Budget for potential administrative procedures and works.

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 →