Indivision: a Sole Application for Boundary Determination without Urgency Is Inadmissible

Picture the scene: in Biscarrosse, in the middle of summer, two brothers inherit a plot of Landes forest. One of them, Paul, discovers that their neighbour has moved the fence a few metres, encroaching on the land. Furious, he alone takes the matter to court to obtain a boundary determination (official delimitation of boundaries) and to have the encroachment recognised. But his brother, Jacques, disagrees: he believes the fence has not moved and that there is no urgency. Can the court act without the agreement of both co-owners? This question, which seems technical, has very concrete consequences for thousands of co-owners (property owned by several persons).

The Court of Cassation, in a judgment of 9 October 1996 (No. 94-15.783), ruled: a boundary determination action brought by a single co-owner is admissible only if it is necessary and urgent to protect the jointly owned property from an imminent peril threatening its material or legal preservation. In short, no proven urgency = no legal action possible for a single co-owner.

For property owners in Biscarrosse, Dax or elsewhere, this decision is a powerful reminder: in co-ownership, you must act together or prove a real urgency. In other words, a neighbourly dispute does not always justify unilateral action.

The facts: a story that happens every day

The case begins with an inheritance. Mrs X. and Mrs Y. are co-owners (joint proprietors) of a plot of land in Biscarrosse. In 1987, Mrs X. notices that Mrs Y. has encroached onto a neighbouring plot belonging to a third party. What to do? Mrs X. decides to act alone: she sues the neighbour for boundary determination to stop the encroachment and protect the jointly owned property.

But Mrs Y. contests: she believes that the boundary determination action is not an urgent measure and that she should have been consulted. The Tribunal de grande instance of Mont-de-Marsan, and then the Cour d'appel of Pau, agree with her: the boundary determination action brought by a single co-owner is inadmissible for lack of urgency and imminent peril. Mrs X. appeals to the Court of Cassation.

On 9 October 1996, the Court of Cassation dismisses her appeal. It confirms that for a co-owner to act alone in court for a preservatory measure (an action aimed at preserving the property), it must be shown that the measure is necessary and urgent to avoid an imminent peril threatening the material or legal preservation of the property. In this case, the urgency was not established. The encroachment, although real, did not immediately endanger the jointly owned land.

What few people know is that urgency is not automatic: a simple encroachment, even if recorded by a bailiff, is not enough. It must be proved that without action, the property risks deterioration or irreparable loss.

The reasoning of the court — broken down

The Court of Cassation relies on the principles governing co-ownership (Articles 815-1 et seq. of the French Civil Code, which organise the management of property owned by several persons). In co-ownership, decisions concerning the property must be taken unanimously, except for acts of administration (routine management) or preservatory acts (urgent measures to preserve the property).

A boundary determination action can only be classified as preservatory if it meets two cumulative conditions: necessity and urgency. For the judges, the mere existence of an encroachment does not automatically create urgency. The encroachment must threaten the material preservation of the property (e.g., risk of collapse, destruction) or its legal preservation (e.g., risk of acquisitive prescription, i.e., the neighbour becoming owner by lapse of time).

In this case, the court of appeal had noted that the bailiff's report of 22 September 1987 established acts of encroachment, but that no element demonstrated an imminent peril. Mrs X. had indeed reported the facts to the Public Prosecutor on 12 November 1988, but without proving that the encroachment was worsening or that the neighbour risked acquiring the plot by prescription (usucaption, a method of acquiring ownership through prolonged possession).

In other words, the Court of Cassation validates the reasoning of the lower courts: a preservatory measure must be justified by a real and current urgency, not by a mere fear. The magistrates thus recall that the protection of the interests of co-owners cannot justify unilateral action without respecting the unanimity rule.

However, note: this decision does not close the door to any individual action. If urgency is demonstrated, for example if a neighbour undertakes works that threaten the stability of a party wall, a single co-owner may act. But the burden of proof is heavy.

What this changes for you — concretely

Co-owner: you cannot bring a boundary determination action alone without the agreement of the other co-owners, unless there is urgency. For example, if you are in Dax and your neighbour builds a fence on your jointly owned land, you must first consult the other owners. If one of them refuses, you will have to apply to the court for permission to act alone, proving urgency (risk of prescription, for example).

Purchaser: before buying a property in co-ownership, check that all co-owners agree on the boundaries. An amicable boundary determination (with everyone's agreement) is preferable. Otherwise, you could inherit a latent conflict.

Tenant: you are not directly affected, but if your landlord is a co-owner, their difficulties may delay works or legal actions. Be vigilant.

In my practice, I have come across cases where a co-owner desperately wanted a boundary determination for a 50 cm encroachment. The cost of the proceedings (lawyer, expert, court fees) can exceed €5,000, with no guarantee of success if urgency is not proven. It is better to attempt conciliation or an amicable agreement.

If you are in this situation, you must gather evidence of urgency: photos, bailiff's reports, witness statements, letters. And above all, try to obtain the written agreement of the other co-owners.

Four tips to avoid this type of dispute

• Draft a co-ownership agreement as soon as the inheritance is opened or the joint purchase is made. This document, signed by all, defines the management rules: who can act alone, for which acts, and how to resolve disagreements. This avoids deadlock.
• In case of encroachment, act collectively: inform all co-owners in writing (registered letter with acknowledgement of receipt). Propose a meeting to decide on the course of action. Unanimous agreement remains the golden rule.
• In case of real urgency, build a solid file: have a bailiff record the state of the premises, the evolution of the encroachment, and any element showing an imminent peril (e.g., threat of collapse). Then apply to the urgent applications judge (référé procedure) for permission to act alone.
• Prefer mediation or conciliation before any court action. A visit to the conciliator of justice in Dax or Biscarrosse can resolve the conflict at lower cost and preserve relationships.

Further reading: related case law and developments

The Court of Cassation reaffirmed this principle in a judgment of 15 December 1998 (No. 96-22.073): a co-owner may act alone for a possessory action (action to protect possession) if urgency is demonstrated. But the trend is constant: judges are demanding on proof of urgency.

A more recent decision, of 23 November 2022 (No. 21-20.417), specifies that even in case of urgency, the co-owner must act in the interest of all, and not for his sole personal interest. This means that a boundary determination action cannot be used to settle a personal conflict between co-owners.

What this means for the future: courts will continue to protect the rights of minority co-owners against abusive unilateral actions. The solution therefore remains consultation or, failing that, prior judicial authorisation.

In practice: what to do

1. Gather all co-owners: hold a meeting to decide on the advisability of a boundary determination. Record the decisions in minutes.
2. If urgency is manifest (worsening encroachment, risk of prescription), gather evidence: dated photos, bailiff's reports, registered letters.
3. Apply to the urgent applications judge for permission to act alone. You will need to demonstrate urgency and necessity of the measure.
4. In the absence of urgency, opt for an amicable boundary determination with everyone's agreement. Use a chartered surveyor to draw up a plan. The cost (around €1,000 to €2,000) is shared among the co-owners.
5. If a co-owner refuses, consider a partition action (exit from co-ownership) to become sole owner.

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 →