Boundary Survey in Co-ownership: The Court of Cassation Shuts the Door on Co-owners

Imagine the scene: you own a beautiful flat with a garden in a co-ownership in La Ciotat. One fine morning, you notice that your neighbour has moved the fence a few dozen centimetres, encroaching on your patch of greenery. Your first instinct? Request a boundary survey (official delimitation of properties) to re-establish the boundaries. Logical, right? Yet the Court of Cassation, in a judgment of 27 April 2000, said exactly the opposite: it is impossible to bring a boundary survey action between co-owners of the same building.

But what does this actually change for you, an owner in Marseille or elsewhere? This decision, often little known, has concrete consequences. It is based on a simple but inexorable principle: a boundary survey is only possible between owners of different plots of land. However, in a co-ownership, the private units (flats, gardens) form part of the same building, even if they belong to different people. The Court deduces that the boundary survey action is inadmissible.

This article will analyse this decision, explain why the judges reasoned as they did, and above all give you practical solutions to protect your rights without falling into this judicial trap. Because while the boundary survey is closed to you, other avenues exist. Follow the guide.

The facts: a story that happens every day

The case giving rise to this judgment opposed the Y... spouses (owners) to the C... spouses (other co-owners) of the same building in co-ownership. The dispute concerned a garden, a private part of the building. The Y... spouses considered that the boundary of their garden was not being respected and summoned the C... spouses for a boundary survey before the tribunal de grande instance.

At first instance, their claim was held admissible. But the C... spouses appealed. The court of appeal reversed the judgment: it declared the boundary survey action inadmissible. Why? Because, according to it, Article 646 of the Civil Code (which allows any owner to compel his neighbour to a boundary survey) requires that the plots to be delimited belong to different owners. However, in a co-ownership, the private units are not distinct plots in the legal sense: they are integrated into the same building, subject to a set of co-ownership regulations.

The Y... spouses appealed to the Court of Cassation. They argued that the boundary survey action is a petitory action (aimed at recognising a right of ownership) and that any co-owner may act individually to defend his unit. But the Court of Cassation dismissed their appeal. It approved the court of appeal: Article 646 of the Civil Code is clear, a boundary survey requires distinct owners, which is not the case between co-owners of the same building. In other words, even if you own your unit, you cannot ask the judge to fix the boundaries with another unit of the same co-ownership.

The reasoning of the court — analysed

To understand this judgment, we must return to the texts. Article 646 of the Civil Code provides: "Any owner may compel his neighbour to the boundary survey of their contiguous properties." The key word is "neighbour": it implies two distinct properties, belonging to different people. In a co-ownership, the units are not independent properties: they are fractions of the same building, governed by a specific legal status (Law of 10 July 1965).

In this case, the court of appeal noted that the disputed garden was part of the building in co-ownership. Consequently, the boundary survey action was inadmissible. The Court of Cassation confirms this analysis. However, note: this does not mean that co-owners are without remedy. As the Y... spouses recalled in their appeal, the boundary survey action is a petitory action (it aims to recognise a right of ownership). Co-owners can take legal action to enforce their private rights, but not through the boundary survey.

What few people know is that this decision is part of consistent case law. The Court of Cassation has already ruled that a boundary survey is not possible between co-owners in indivision (people who own a property together) nor between co-owners. However, a co-owner can bring a revendication action (petitory action) to assert his right of ownership over a part of the unit, or a possessory action (to protect his possession) if the disturbance is recent.

In short, the judges made a strict application of the letter of Article 646. But their reasoning is logical: the purpose of a boundary survey is to fix a boundary between two autonomous plots. In a co-ownership, the boundaries are already defined by the co-ownership regulations and plans. If a co-owner encroaches, it is a violation of his title deed, not a boundary problem.

What this changes for you — concretely

So, concretely, what to do if you are faced with an encroachment between co-ownership units? Here are the implications by profile:

• Landlord owner: You rent out your flat in Marseille. If your tenant reports an encroachment by the neighbour, you cannot request a boundary survey. You must check your title deed and bring a petitory action (recognition of your right) before the tribunal judiciaire. Expect several months and legal fees (often €1,500 to €3,000).
• Occupying co-owner: You live in your unit in La Ciotat. If your neighbour has moved a fence, you can try mediation or contact the managing agent. If that fails, a possessory action (if the disturbance dates back less than a year) is faster and less expensive than a petitory action. Timescale: about 6 months.
• Purchaser: Before buying a unit with a garden, demand an amicable boundary survey plan (agreement between the co-owners) or a notarial certificate on the boundaries. In case of doubt, a suspensive condition (a condition that cancels the sale if the boundary survey is not possible) can protect you.

If you are in this situation, you must absolutely avoid bringing a boundary survey action before the judge: your action would be inadmissible, and you would waste time and money. Opt instead for a revendication action or a possessory action. undefined, I have come across cases where co-owners in Marseille attempted a boundary survey and hit this procedural bar. They had to start their proceedings again.

Four tips to avoid this type of dispute

• Keep all documents relating to your unit: co-ownership regulations, plans, deed of sale. They constitute proof of your boundaries.
• Have an amicable boundary survey carried out: with the agreement of all co-owners concerned, a surveyor can fix the boundaries. This avoids litigation.
• In case of conflict, act quickly: the possessory action is subject to a one-year limitation period from the disturbance. After this period, you lose this fast track.
• Consult a lawyer lawyer: before taking any action, a lawyer will guide you towards the appropriate procedure. In Marseille, co-ownership disputes are common; good advice will save you from mistakes.

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

Further reading: related case law and developments

The position of the Court of Cassation is consistent. In a judgment of 12 December 1990 (no. 89-13.998), it had already ruled that the boundary survey action is not available between co-owners in indivision. The same logic applies to co-owners. More recently, the Court recalled that the boundary survey is a real action (relating to property) and a personal action (between owners), and that it requires distinct properties (Civ. 3e, 27 March 2019, no. 18-10.737).

This case law shows a tendency towards strictness: the judges do not want the boundary survey to be used to settle internal co-ownership conflicts. They consider that the co-ownership regulations and title deeds are sufficient to determine the boundaries. For the future, it is unlikely that the Court will change its mind. However, co-owners could turn to mediation or arbitration (private dispute resolution procedure).

Checklist before acting

1. Identify the problem: is it an encroachment (illegal construction) or simply a disagreement over the boundary?
2. Check your title deed: what do the plans and the co-ownership regulations say?
3. Date the disturbance: how long has the encroachment existed? Less than a year? Possessory action possible.
4. Contact the managing agent: sometimes a simple reminder of the regulations suffices.
5. Consult a lawyer: to choose the right action (petitory or possessory) and avoid inadmissibility.

Are you 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 →