Article L. 631-7 CCH: nullity of commercial lease in a dwelling – Cass. civ. 1993

Imagine: you are the owner of a flat in Mougins, let for years to a tenant. The tenant dies, and his heirs decide to turn the premises into a hairdressing salon, without asking your permission or obtaining any administrative authorisation. You discover the situation, feel betrayed, and wonder: "Can I annul the lease and recover my property?"

This is exactly the issue that arose in a case decided by the Cour de cassation on 8 December 1993 (appeal no. 92-15.348). The landlord invoked Article L. 631-7 of the Construction and Housing Code, which prohibits changing the use of a dwelling without authorisation, to seek the nullity of the lease. However, the court gave a nuanced decision, depending on the date of the contract and the initial use of the premises.

In this article, I will tell this story as if it were happening to you, break down the judges' reasoning, and above all give you practical keys to avoid finding yourself in such a deadlock. Whether you are a landlord in Grasse, a tenant, or a property professional, this decision concerns you.

The facts: a story that happens every day

Mr X is the owner of a flat in Mougins, in the Alpes-Maritimes. He let it to a tenant, Mr Y, under a lease signed in 1985. The contract specifies that the flat is for "exclusive residential use". The tenant lives there with his family.

In 1990, Mr Y dies. His heirs, who take over the lease, decide not to live there. They convert the flat into commercial premises: they set up a clothing retail business. No authorisation is sought from the mayor or the landlord. Mr X discovers the situation a few months later when the new tenants (the heirs) stop paying rent.

Mr X then sues the heirs to seek termination of the lease (i.e. the end of the contract) for non-payment of rent and unauthorised change of use. On appeal, he adds a claim: nullity of the lease on the basis of Article L. 631-7 of the Construction and Housing Code. This article, applicable in municipalities like Mougins (subject to the Law of 1 September 1948), prohibits using a residential premises for another purpose without prior administrative authorisation. Nullity is supposed to strike any agreement or contract concluded in violation of this prohibition.

The Court of Appeal rules in favour of the landlord: it pronounces the nullity of the lease. The heirs appeal to the Cour de cassation. The case comes before the Cour de cassation, which must decide: can a lease concluded before the law came into force (or before the heirs changed the use) be annulled?

The court's reasoning — broken down

The Cour de cassation quashes (annuls) the Court of Appeal's decision. It considers that the lower court judges misapplied Article L. 631-7. Why? Because this provision provides for the nullity of "agreements or contracts concluded in violation" of the prohibition on change of use. In other words, if the lease was validly concluded for residential use, and it is only later that the tenants change the use without authorisation, nullity cannot affect the lease itself. The contract remains valid; it is the use that is unlawful.

In clear terms, nullity only applies to contracts that, from their inception, relate to a prohibited change of use. For example, if a landlord rents a dwelling knowing it will be used as a shop without authorisation, that lease would be void. But if the lease is initially compliant (residential use), and the tenant subsequently transforms it without right, the landlord cannot invoke nullity to terminate the lease. Instead, he must seek termination for breach of contractual obligations (for example, for violation of the exclusive residential use clause).

In this case, the lease dated from 1985, well before the transformation. It had been concluded "with reference to Article 3 quinquiès of the Law of 1 September 1948", meaning it was a standard residential lease. The heirs then used the premises for commercial purposes, but this does not render the lease void ab initio (from the start). The court clarifies that the nullity provided for by Article L. 631-7 does not apply to such a contract.

In other words, the court distinguishes two situations: on the one hand, contracts that directly violate the prohibition (for example, a commercial lease concluded without authorisation in a dwelling); on the other hand, valid contracts whose performance is diverted. In the latter case, the landlord must act on the ground of contractual non-performance, not nullity.

What this changes for you — practically

If you are a landlord in Grasse or elsewhere, this decision has a direct impact on your legal strategy. If your tenant transforms your flat into commercial premises without your agreement and without authorisation, you cannot seek nullity of the lease. You must invoke the residential use clause (if it appears in the contract) or the general obligation of peaceful enjoyment. Judicial termination of the lease is possible, but you will need to prove a serious breach by the tenant. Allow between 6 and 12 months for proceedings, depending on the workload of the competent judicial court.

For tenants or their heirs: be aware that changing the use of a dwelling without authorisation exposes you to risks. The landlord can obtain termination of the lease, and you could be ordered to pay damages for the harm suffered (for example, loss of value of the property or reinstatement costs). In addition, the town hall may impose a fine and require you to restore the premises to residential use. In Mougins, applying for authorisation to change use is compulsory and subject to strict conditions (compensation by creation of social housing, etc.).

For buyers: if you purchase a property that has been transformed without authorisation, you may have to restore it at your own expense. Always check the declared use in the deeds and whether administrative authorisation exists if the property is used for commercial purposes. A competent notary will alert you, but if in doubt, ask for a certificate from the town hall.

undefined, I have come across cases where landlords in Grasse wasted years trying to annul a lease when they should have sought termination. Result: unpaid rent and longer proceedings. Knowing this distinction saves you valuable time.

Four tips to avoid this type of dispute

• Draft a precise use clause in the lease: expressly state that the dwelling is for exclusive residential use, and prohibit any commercial activity, even partial. Add a forfeiture clause (automatic termination in case of breach).
• Check the actual use of the premises regularly: do not wait until the tenant stops paying. A vigilant landlord can commission a bailiff's report every two years, or ask for a professional home insurance certificate.
• If transformation occurs without authorisation, act quickly: send a formal notice to the tenant to cease the activity within 15 days. If nothing changes, refer the matter to the judicial court for termination of the lease. Do not attempt nullity, it would be a mistake.
• If you are a tenant and wish to carry out a professional activity at home: check your lease and local regulations. For a liberal profession or commercial activity, authorisation to change use may be necessary. Seek advice from a lawyer before starting.

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

Further reading: related case law and developments

This 1993 decision is in line with a consistent line of the Cour de cassation: the nullity under Article L. 631-7 is reserved for contracts that, from their conclusion, violate the prohibition. In a judgment of 18 May 1994 (no. 92-15.348 bis), the court confirmed this position for a commercial lease signed without authorisation in a dwelling. Conversely, if the lease is subsequent to the transformation (for example, the landlord knowingly rents a dwelling for commercial use), nullity may be pronounced.

Since then, the ALUR law of 2014 has strengthened penalties for change of use: civil fine of up to €50,000, obligation to restore the property, and possibility for the town hall to acquire the property. The courts are increasingly strict. The trend is towards protecting the rental stock, especially in high-pressure areas like the Côte d'Azur.

For the future, if you are a landlord, remember that nullity is not an option when the lease was validly concluded. Rely on termination for non-performance. If you are a tenant, be wary of unauthorised transformations: the consequences can be serious.

Checklist before taking action

FAQ: Practical questions

Q: Can I annul the lease if my tenant turns my flat into a shop?
A: No, not on the basis of Article L. 631-7 if the lease was concluded for residential use. You must seek judicial termination of the lease for breach of the tenant's obligations.

Q: What should I do if I discover that my tenant is using the premises for commercial activity without authorisation?
A: Send a formal notice to cease within 15 days. If nothing changes, refer the matter to the judicial court. At the same time, report the situation to the town hall, which may initiate administrative proceedings.

Q: What are the time limits for taking action?
A: The limitation period is 5 years from the discovery of the change of use. But act quickly: the longer you wait, the harder it will be to prove the harm.

Q: How much does a lease termination procedure cost?
A: Allow between €1,500 and €5,000 in lawyer's fees, depending on complexity. Court costs (bailiff, etc.) are additional. A preliminary 45-minute consultation with a lawyer (around €200) can save you costly mistakes.

Q: Can I claim damages from the tenant?
A: Yes, if you prove harm (e.g. loss of property value, reinstatement costs, unpaid rent). The amount is set by the judge based on the evidence provided.

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 →