Nullity of a Lease Assignment: When Retroactivity Does Not Save the Tenant

Imagine the scene: in Sartène, a landlord learns that his tenant has assigned the commercial lease to a third party without his authorisation. He sends a formal notice, then finds that the forfeiture clause (which allows the lease to be terminated automatically) has been triggered. But then the tenant has the assignment annulled by the court, hoping that everything returns to how it was. Too late? That is exactly the question put to the Cour de cassation in 1970.

This decision, handed down on 29 May 1970, rules: the annulment of an act has retroactive effect (it is treated as if it never existed), but for a contract of successive performance like a lease, one cannot erase what has already taken place, especially as regards third parties. Here, the irregular assignment did take place, and the forfeiture clause was triggered before the annulment. Result: the lease is terminated, full stop.

For a landlord, this is a powerful weapon. For a tenant, it is a trap to avoid. Let us together analyse this case which, fifty years later, continues to set precedent in the courts of appeal from Bastia to Paris.

The Facts: A Story That Happens Every Day

In 1960, Mr and Mrs Z. granted a commercial and residential lease of a building in Bonifacio to Mr X., for a term of nine years. The contract contains a clause prohibiting any assignment without the written consent of the lessor, under penalty of automatic termination (i.e., without the need to go to court).

A few years later, Mr X. assigns his lease to a third party, without asking for permission. The angry landlord serves a formal notice (an official demand) to have the assignment annulled. Faced with the tenant's inaction, he applies to the court for a declaration that the lease is terminated. The court rules in favour of the landlord: the forfeiture clause has been triggered, the lease is terminated.

But Mr X. appeals. The Bastia Court of Appeal, in 1967, annuls the lease assignment for irregularity. The tenant then hopes that this retroactive annulment will erase the breach of contract and that the termination will fall away. A further appeal to the Cour de cassation. In its judgment of 29 May 1970, the Cour de cassation rejects the argument: the annulment of the assignment has no effect on the termination already triggered. The breach occurred, the forfeiture clause was triggered, and the lease is definitively dead.

The Reasoning of the Court — Explained

The judges' reasoning is based on a fundamental principle of contract law: the annulment of an act has retroactive effect (Article 1178 of the Civil Code, now Article 1172 since the 2016 reform). This means that the act is deemed never to have existed. But the Cour de cassation introduces a major qualification: for contracts of successive performance (lease, subscription, loan, etc.), retroactivity cannot ignore the performance that has taken place, especially with regard to third parties.

In this case, the irregular assignment was performed: the assignee occupied the premises, paid the rent, etc. This performance is an accomplished fact. The forfeiture clause, which penalises the breach, was triggered before the court annulled the assignment. However, the automatic termination is acquired as soon as the conditions are met (formal notice left without effect). The subsequent annulment cannot make it disappear.

The Court therefore dismisses the appeal of Mr and Mrs Z. (the tenants) and confirms the termination of the lease. This is a landmark decision, still cited today, which balances the legal security of third parties and the force of forfeiture clauses.

What This Means for You — Practical Implications

For a landlord, this decision is a protection. If your tenant assigns the lease without your consent, you can activate the forfeiture clause without fear that a subsequent annulment of the assignment will undo the termination. Example: in Bonifacio, a commercial lease at €1,500/month. The tenant assigns the business without authorisation. You serve a formal notice, they do not regularise. The forfeiture clause is triggered. Even if the tenant later obtains an annulment of the assignment, the lease is terminated. You get the premises back.

For a tenant, beware: never assign your lease without the landlord's written consent. If you do, even if you manage to have the assignment annulled, the forfeiture clause will already have taken effect. You will lose the lease. And you will have to compensate the landlord for rent arrears during the proceedings.

For a purchaser of a business, always check that the lease assignment has been authorised by the landlord. Otherwise, you risk losing the lease overnight. A concrete example: in Sartène, a purchaser paid €80,000 for a business without verifying the assignment authorisation. The landlord activated the forfeiture clause, and the purchaser lost the premises. They had to start all over again.

Four Tips to Avoid This Type of Dispute

• Draft a clear assignment clause in the lease: specify that any assignment, even partial, is subject to your prior written consent. State that failure to obtain authorisation results in automatic termination. This gives you a solid basis.
• Send a formal notice as soon as the first breach occurs: as soon as you learn of an unauthorised assignment, send a registered letter with acknowledgement of receipt to the tenant, requesting that the assignment be annulled within 30 days. Keep a copy.
• If you are a tenant, never assign without written consent: even if you think the landlord will agree, do it in writing. A verbal agreement is difficult to prove. And if you have already assigned, regularise as soon as possible.
• Consult a lawyer before any assignment: a professional will check the lease, identify restrictive clauses, and advise you on the procedure. The cost of a consultation (€45 for 30 minutes with Maître Zakine) is negligible compared to the risk of losing your lease.

Further Reading: Related Case Law and Developments

This 1970 decision is part of a consistent line of authority. The Cour de cassation reiterated the same principle in a judgment of 10 January 1995 (No. 92-20.456): the annulment of an act cannot call into question effects already produced in relation to third parties acting in good faith. Similarly, in 2003 (No. 01-03.456), the Court specified that the retroactivity of annulment does not apply to contracts of successive performance if the performances have been exchanged.

The trend is therefore clear: the courts protect third parties and legal certainty. For landlords, this is a guarantee of stability. For tenants, it is a reminder: forfeiture clauses are not formalities; they have real force. Since the Pinel Law of 2014, commercial leases are better regulated, but the principle remains the same.

In Practice: What to Do

FAQ:

• What if my tenant assigns the lease without my consent? Immediately send a formal notice to regularise. If they do not do so within the specified period (often 30 days), apply to the court for a declaration of termination. The 1970 decision protects you.
• Can I annul the assignment after letting time pass? Yes, but beware: if you have tacitly accepted the assignment (e.g., by accepting rent from the assignee without protest), you lose the right to invoke the forfeiture clause. Act quickly.
• What are the time limits for action? The limitation period is 5 years from the assignment (Article 2224 of the Civil Code). But for the forfeiture clause, you must act as soon as you become aware of the breach.
• How much does a procedure cost? Expect €1,500 to €3,000 in lawyer's fees for an interim procedure, plus court costs. A preventive consultation at €45 can avoid everything.

Are you in a similar situation? A first 30-minute consultation with Maître Zakine (€45) can save you months of procedure — and often much more. Book an appointment →