Development: When building setback rules become final (even after 10 years)

Imagine: you have just bought a house in a development in Rambouillet, in the Yvelines département. You are proud of your house with garden. But your neighbour, Mr. Dupont, decides to build an extension that encroaches on the boundary line, only 2 metres away instead of the 4 metres required by the development regulations. You check the specifications: they stipulate a 4-metre setback. But the development was approved 12 years ago. Has the 10-year period expired? Are the rules obsolete?

This question is asked by hundreds of owners every year. The answer lies in a judgment of the French Supreme Court of 11 January 1995 (No. 92-18.456), which ruled on a similar dispute between owners in the commune of Saint-Loup Cammas, near Toulouse. The issue: to determine whether the building setback rules contained in the approved regulations of a development are planning rules (therefore subject to the 10-year period) or contractual obligations (perpetual). Spoiler: the Court said they were regulatory, but watch out for the starting date of the period.

In this article, I will analyse this decision, explain what it changes for you, and give you practical advice to avoid nasty surprises. Whether you are an owner in Trappes, a buyer in Rambouillet, or a property professional, you will leave with a clear understanding of your rights and obligations.

The facts: a story that happens every day

Mr. X and Mrs. Y are owners of neighbouring plots in a development located in Saint-Loup Cammas, a commune in the Toulouse suburbs. The development was approved by prefectural order in 1976. The development regulations, approved at that time, impose a minimum setback of 4 metres from plot boundaries for any construction. In 1988, Mr. X builds an extension that does not comply with this rule: his building is only 2 metres from the boundary. Mrs. Y sues him to have the construction demolished, relying on the development regulations.

Before the Tribunal de grande instance of Toulouse, Mr. X raises a significant argument: according to him, the planning rules of the development have been obsolete since 6 January 1986, because the 10-year period provided for by Article L. 315-2-1 of the French Planning Code (now codified in Article L. 442-9) has expired. This period runs from the date of the development permit. Furthermore, a local land-use plan (POS) was approved in the commune in 1983, which, according to him, replaces the development rules. Mrs. Y retorts that the setback rules are not planning rules but contractual clauses of the specifications, therefore perpetual.

The tribunal rules in favour of Mrs. Y at first instance: it orders demolition. Mr. X appeals. The Court of Appeal of Toulouse, in a judgment of 16 June 1992, reverses the decision: it considers that the provisions of the regulations are planning rules that ceased to apply at the end of the 10-year period, and that the POS has replaced them. Mrs. Y appeals to the Supreme Court.

The Supreme Court, in its judgment of 11 January 1995, quashes the appeal judgment. It criticises the Court of Appeal for having violated Articles 1134 and 1143 of the French Civil Code (former, now 1103 and 1221) relating to the binding force of contracts, together with Article L. 315-2-1 of the Planning Code. The High Court recalls that the provisions relating to the setback of buildings from plot boundaries, contained in the approved regulations of a development, are regulatory in nature. And above all, that the 10-year period runs from the date of the development permit, not from the approval of the regulations.

But what does that change exactly? In this case, the development dated from 1976, so the 10-year period had expired in 1986, before the disputed construction in 1988. Yet the Supreme Court quashes the appeal judgment that had held the rules obsolete. Why? Because the Court of Appeal did not verify whether the POS had actually replaced the development rules. And above all, it did not distinguish between planning rules (which can be replaced) and contractual clauses of the specifications (which remain).

In short, the Supreme Court says: setback rules are regulatory, therefore subject to the 10-year period. But this period runs from the date of the development permit. And even after 10 years, these rules may survive if the local plan (formerly POS) has not expressly repealed them. Moreover, the specifications (contractual part) remain applicable indefinitely between co-owners of plots.

The reasoning of the court — analysed

The Supreme Court relies on two legal pillars: on the one hand, Article 1134 of the Civil Code (now 1103) which provides that "agreements lawfully entered into take the place of law for those who have made them". On the other hand, Article L. 315-2-1 of the Planning Code (former) which set a 10-year period for the application of the planning rules of the development.

What many do not know is that the regulations of a development have a dual nature: they contain both planning rules (setback, height, appearance) and contractual clauses (easements, charges, restrictions). The former are subject to the 10-year period provided for by Article L. 315-2-1, while the latter remain perpetual between co-owners of plots. But be careful: the distinction is not always obvious. The Supreme Court specifies here that the rule of setback from plot boundaries is a planning rule, therefore regulatory.

In other words, once the 10-year period has expired, these planning rules may be replaced by the local plan. But if the local plan says nothing on this point, the development rules continue to apply. In this case, the Court of Appeal had considered that the POS had replaced the development rules, but without verifying whether the POS contained equivalent provisions. The Supreme Court criticises it for this lack of verification.

What is interesting is that the Supreme Court does not say that the rules were still applicable in this case. It quashes the judgment for lack of legal basis, and refers the case to another Court of Appeal. But it lays down a clear principle: the 10-year period runs from the date of the development permit, not from the approval of the regulations. And above all, obsolescence is not automatic: the local plan must have actually repealed the development rules.

undefined, I have come across cases where owners in Trappes thought they could build anything after 10 years, without referring to the development regulations. This is a mistake. The regulations remain in force as long as the local plan has not replaced them. And even if the local plan replaces them, the contractual clauses of the specifications (such as the obligation to fence, easements of way, etc.) survive and bind the co-owners of plots.

What this changes for you — practically

So, how should you react? Here are the practical implications by profile:

For the owner of an old plot (more than 10 years): You think you can build freely? Think again. The development regulations may still apply if the local plan has not repealed them. Before starting work, check the date of the development permit. If it is less than 10 years old, the planning rules of the development are in force. If it is more than 10 years old, look at the local plan: if it repeats the same rules, they apply. If it is silent, the development regulations continue to apply. And above all, do not forget the specifications: contractual restrictions (e.g., prohibition of fencing, obligation to maintain common parts) are perpetual. In Rambouillet, I saw an owner who wanted to divide his land into two plots: the specifications prohibited it, and he had to give up.

For the buyer of a plot: Before buying, ask for the development regulations and the specifications. Check the date of the development permit. If it is recent, the planning rules are still current. If it is old, ask the seller whether the local plan has modified the rules. And above all, read the contractual clauses: some may limit the use of your property (e.g., no holiday rentals, no satellite dish). If you buy without checking, you could face a demolition action from a neighbour. Example: in Trappes, a buyer bought a house with a project to add a storey, but the regulations limited the height to 6 metres. He had to abandon his project, a loss of €15,000 in architect's fees.

For the property professional (agent, developer): You must inform your clients of the existence of the regulations and specifications. If you fail to do so, you may be held liable. A developer in Versailles had to compensate buyers to the tune of €50,000 because he did not mention that the development prohibited swimming pools.

For the co-owner of a development plot: If a neighbour does not comply with the setback rules, you can take action. But be careful: for planning rules, the 10-year period may be an obstacle if the local plan has replaced them. On the other hand, for contractual clauses, the action is not subject to any limitation period (no time limit). You can therefore seek demolition of a construction contrary to the specifications, even 20 years later.

Four tips to avoid this type of dispute

• Consult the regulations and specifications before any purchase or works. Do not rely solely on the information from the seller or agent. Ask for the documents from the development management company or the town hall. Have them analysed by a lawyer if necessary.
• Check the date of the development permit. It appears in the deed of sale or can be obtained from the town hall. If it is more than 10 years old, ask the planning department whether the local plan has adopted or repealed the development rules.
• Before building, make a preliminary declaration or apply for a building permit. Even if you think the development rules no longer apply, the town hall will process your application based on the local plan and the development regulations. If it grants you permission, you will be protected in the event of a challenge by a neighbour.
• In case of a dispute, do not overlook the limitation period. For planning rules, the demolition action must be brought within 10 years of the development permit. But for contractual clauses, there is no limitation period. If your neighbour built 15 years ago in breach of the specifications, you can still take action.

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Further reading: related case law and developments

This 1995 judgment is part of a line of decisions that clarify the legal regime of developments. Before it, the Supreme Court had already held, in a judgment of 13 January 1987 (No. 85-14.616), that the planning rules of a development cease to apply after 10 years, unless the local plan maintains them. But the 1995 judgment adds an important clarification: the period runs from the date of the development permit, not from the approval of the regulations.

Since then, case law has evolved. The ALUR law of 2014 amended Article L. 442-9 of the Planning Code (successor to Article L. 315-2-1). Now, the planning rules of a development become obsolete at the end of a 10-year period from the date of the development permit, unless the development is located in a safeguarded sector or the local plan provides otherwise. But the distinction between regulatory rules and contractual clauses remains.

What few people know is that the Courts of Appeal continue to be divided on the scope of this case law. Some consider that the specifications are entirely contractual, others that they may contain planning rules. The Supreme Court has ruled for setback rules, but other rules (height, appearance) may be analysed differently. In practice, it is prudent to consider that all rules in the regulations are potentially binding, and always check the local plan.

Summary and next steps

FAQ:

1. Do the rules of a development apply after 10 years? Yes, if they are contractual (specifications) or if the local plan maintains them. The planning rules of the regulations become obsolete after 10 years, but be careful: the period runs from the date of the development permit.
2. Can I build on the boundary line if the regulations prohibit it? No, as long as the regulations are in force. Even after 10 years, check the local plan and the specifications.
3. What if my neighbour builds in breach of the regulations? Act quickly. For planning rules, you have 10 years from the date of the development permit. For contractual clauses, you can act without time limit.
4. What is the cost of a demolition action? Expect between €3,000 and €10,000 in legal fees, plus expert and bailiff costs. But a preventive 45-minute consultation with a lawyer (about €150) can save you this cost.
5. Can I request a derogation from the development regulations? No, the regulations can only be modified by unanimous consent of the co-owners of plots. In practice, this is very difficult. Better to check before buying.

In summary, remember that the regulations of a development are not a mere historical document. They can have very concrete consequences on your property project. Whether you are in Rambouillet, Trappes or elsewhere, take the time to study them with a professional.

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