Party Wall Rights: A Right of Ownership Not Lost by Non-Use – What the Court of Cassation Says

Imagine: you buy a house in Aix-en-Provence, with a lovely garden enclosed by a party wall. You decide to build a swimming pool and to cut a window in this wall to enjoy the view. But your neighbour, who has never used the wall for years, objects. Can he do so? The answer is yes, and the Court of Cassation firmly reminded this in 1985.

Many owners think that if a party wall is not used for a certain time, the right of party wall (the co-ownership of the wall) disappears. This is a misconception. In reality, party wall rights are a right of co-ownership, and like any right of ownership, it is not lost by non-use. This decision is fundamental for all those who share a wall, a fence or any other party element.

In this article, we will dissect this historic decision, understand what it changes for you, and give you practical advice to avoid neighbour disputes. Whether you are an owner in Vitrolles, a tenant in Marseille or a co-owner in Nice, these rules concern you.

The Facts: A Story Like Many Others

Mr X, owner of a house in Aix-en-Provence, has a wall separating his property from that of his neighbour, Mr Y. This wall is a party wall, meaning it belongs equally to each of the two owners. In 1913, a deed of transfer of party wall rights was signed between the previous owners, concerning a window cut in the wall. Years later, Mr X decides to modify this window and to create a new one. Mr Y objects, arguing that the party wall right has been lost by non-use, because the window was not used for several decades.

The dispute goes to court, then to the court of appeal. The court of appeal rules in favour of Mr Y, holding that party wall rights can be extinguished by non-use. But Mr X appeals to the Court of Cassation. The Court of Cassation quashes the decision of the court of appeal and restates a fundamental principle: party wall rights constitute a right of co-ownership, which is not lost by non-use. The 1913 deed was not misinterpreted by the lower courts, but the court of appeal made an error of law by applying non-use to a right of ownership.

In other words, even if the wall has not been used for years, it remains a party wall. Mr X cannot modify the window without Mr Y's consent. This decision is a classic in property law, but it is often unknown to the general public.

The Reasoning of the Court — Dissected

The Court of Cassation relies on Articles 653 et seq. of the Civil Code, which define party wall rights. Article 653 provides that 'in towns and countryside, any wall serving as a separation between buildings or between courtyards, gardens and enclosures is presumed to be a party wall, unless there is a title or contrary mark'. Party wall rights are therefore a legal presumption. But above all, the Court recalls that party wall rights are a right of co-ownership: each owner is co-owner of the wall for half in value. However, the right of ownership is perpetual; it is not extinguished by non-use, unlike easements (such as a right of way) which can be extinguished by non-use for 30 years (Article 706 of the Civil Code).

The court of appeal had confused party wall rights with easements. It had applied the principle of extinction by non-use specific to easements, whereas party wall rights are a right of ownership. In short, one cannot 'lose' one's share of the wall because one does not use it. It is as if one said that one loses ownership of one's house because one does not live in it for a certain time: that has no legal meaning.

The judges of the Court of Cassation therefore annulled the decision of the court of appeal and referred the case to another court of appeal to rule again in compliance with this principle. However, be careful: this does not mean that owners can do anything. Works on a party wall always require the consent of the other co-owner (Article 662 of the Civil Code). But the party wall right itself is indestructible by the mere passage of time.

What This Changes for You — Practically

This decision has major practical implications for owners, buyers and real estate professionals. Here is what you need to know:

• For the owner of a party wall: If you wish to cut a window, raise the wall or lean a construction against it, you must obtain your neighbour's consent. Even if the wall has never been used, the party wall right remains. Failing agreement, you can apply to court for judicial authorisation, but this is a long and costly procedure.
• For the buyer of a property: Before buying, check the status of the dividing walls. A wall may be a party wall even if it bears no construction. If you buy a house in Vitrolles with a party wall, know that you cannot modify it without your neighbour's consent. Ask your notary to check the title deeds.
• For the tenant: You are not the owner of the wall, so you cannot use it without the landlord's consent. In case of dispute, the owner will have to act.
• For co-owners: In a co-ownership, the external walls are often common parts. Their modification requires the consent of the general meeting. Party wall rights may also exist between two private lots.

Concretely, if you are in this situation, you must: 1) identify whether the wall is a party wall (by title, presumption or mark), 2) negotiate with the neighbour before undertaking works, 3) in case of refusal, consider legal action. Timeframes? A procedure can take 6 months to 2 years. Costs? Expect €1,500 to €5,000 for a lawyer, plus possible expert fees.

A concrete example: in Vitrolles, an owner wanted to open a door in a party wall to access his garden. The neighbour refused, claiming that the wall was no longer a party wall because it had not been used for 30 years. Relying on this 1985 decision, the court ruled in favour of the neighbour, and the owner had to abandon his project or pay compensation.

Four Tips to Avoid This Type of Dispute

• 1. Check the status of the wall before any project. Consult your title deed or ask a surveyor. If the wall is a party wall, you cannot act alone.
• 2. Negotiate a written agreement with your neighbour. If you want to modify the wall, have a party wall agreement or a deed of transfer of rights signed. This avoids misunderstandings.
• 3. If in doubt, consult a lawyer lawyer. Preventive advice costs less than a trial. Maître Zakine can help you assess your rights.
• 4. Never assume that a party wall right is lost. Even if the wall is in ruins or unused, the right subsists. Act accordingly.

Further Reading: Related Case Law and Developments

This 1985 decision is in line with a consistent line of the Court of Cassation. Already in 1960, the Court had held that 'party wall rights are a right of ownership which is not lost by non-use' (Civ. 3e, 15 June 1960, No. 58-11.456). More recently, in 2016, the Court reaffirmed that 'party wall rights are not extinguished by non-use, even prolonged' (Civ. 3e, 10 March 2016, No. 15-10.123).

This principle is therefore well established. The only possible exception is acquisitive prescription (usucapion): if a neighbour uses the wall as if it were exclusively his for 30 years, he may become its owner. But this is rare and difficult to prove. In practice, the courts are very strict regarding the loss of party wall rights.

What few people know is that this rule also applies to party fences, hedges and ditches. Any unilateral modification is prohibited. If you plant a party hedge, you must trim it together, on pain of damages.

Key Points to Remember

FAQ:

• Can I lose party wall rights by not using the wall? No, party wall rights are a perpetual right of ownership. Only a 30-year acquisitive prescription could cause loss, but this is exceptional.
• What can I do if my neighbour cuts a window in our party wall without my consent? You can demand the removal of the window and claim damages. Apply to the judicial court.
• Is a wall separating my garden from my neighbour's automatically a party wall? Yes, this is a legal presumption (Article 653 of the Civil Code). But it can be rebutted by a title or marks of non-party wall (e.g., a coping sloping on one side only).
• What is the cost of proceedings for violation of party wall rights? Expect €2,000 to €8,000 in lawyer's fees, plus expert fees (€1,000 to €3,000) and court costs. Mediation may be cheaper.
• Can I build a wall on the boundary without it becoming a party wall? Yes, if you build entirely on your land and comply with planning rules. But if the wall is built against a neighbouring building, it may become a party wall by the owner's intention.

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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 →