Voluntary Intervention in Commercial Law: A Key Decision for Landlords and Tenants

Imagine yourself in Uzès, the owner of commercial premises that you lease to a trader. One day, you receive a court summons: your tenant is applying for a determination of the rent for the renewed lease. So far, nothing unusual. But what happens if another person, say a company that has bought the business, intervenes in the proceedings to also claim something? Is this intervention valid? Can it save a poorly brought action? This is precisely the question the Cour de cassation decided in 2010, in a landmark decision. And the answer is surprising: the intervener who has a right of their own can act independently of the main action. In other words, even if the initial claimant has sued the wrong party, the intervener can still succeed. Alès, Nîmes, or elsewhere, this rule changes the game for commercial leases.

But what exactly does this change for you, landlord or tenant? This decision protects those who have a legitimate interest to act, even if the initial action is inadmissible. For example, if you buy a business and the seller had already started a lease renewal procedure, you can intervene to defend your rights. And if the seller had made a mistake in their application, you are not bound by it. The judges must examine your personal situation. This is a breath of fresh air for property professionals, but also a trap for landlords who think that the inadmissibility of the main action closes all debate.

In this article, I will explain the facts of this case, the judges' reasoning, and above all what you must do to avoid a dispute. As a solicitor specialising in property law, I have seen similar cases in Nîmes or Montpellier, where landlords have been caught off guard. So, read carefully: this case law could save you or cost you dearly.

The facts: a story like many others

Let's go back to 2006. A company, let's call it "Company A", is the tenant of commercial premises in Uzès, in the Gard. The lease is granted by an owner, Mr X. But the land on which the premises are built is subject to a building lease (a contract where the lessee builds on the lessor's land). Company A is not the lessee of the building lease: it is another company, "Company B", that holds that right. Company A sues Mr X before the commercial rent judge to fix the rent for the renewed lease. Problem: Mr X is not Company A's landlord? Yes, he is, but he is not the owner of the land? In reality, the situation is complex: the premises were built by Company B on Mr X's land, then leased to Company A. But Company B later becomes the owner of the land (it exercises its right of superficies). So, who is the real landlord? Company A sues Mr X, but in the meantime, Company B, now the owner, voluntarily intervenes in the proceedings to also ask for a rent determination. The question arises: is Company B's intervention admissible? Can it regularise Company A's action, which is inadmissible because it sued the wrong person?

The Nîmes Court of Appeal, in 2009, said no: Company B's intervention cannot regularise Company A's action, because the main action (Company A's) is inadmissible. Company B should have acted itself from the outset. But the Cour de cassation, in 2010, set aside this judgment. It held that the Court of Appeal had not drawn the consequences of its own findings: it had found that Company B had become the owner of the land, so it had a right of its own, distinct from that of Company A. Company B's voluntary intervention was not linked to the outcome of the main action. In short, even if Company A's action was inadmissible, Company B could still act to assert its right to lease renewal. The trial judges must examine the intervention on its own merits.

The court's reasoning — broken down

To understand this decision, we must revisit the rules on voluntary intervention. In civil procedure, a person may intervene in ongoing proceedings if they have an interest in preserving their rights. A distinction is made between ancillary intervention (to support a party) and principal intervention (to claim a right for oneself). In this case, Company B made a principal intervention: it sought a rent determination in its own name, because it had become the owner of the land and therefore the landlord. Article 330 of the Code of Civil Procedure (which governs voluntary intervention) provides that principal intervention is admissible only if its author has the right to act in respect of the claim they make. Here, Company B indeed had that right, since it was the owner. But the Court of Appeal considered that the intervention could not regularise Company A's inadmissible action. The Cour de cassation corrected this: the fate of the intervention is not linked to that of the main action. In other words, the intervener who relies on a right of their own may be admissible even if the main action is dismissed.

This reasoning is based on the principle of autonomy of principal intervention. The judges found that Company B had a distinct interest: it was the owner, whereas Company A was only the tenant. The confusion arose because Company B had initially granted a building lease, then became the owner. In law, a building lease confers on the lessee a real property right (a right in rem), which explains why Company B could become the owner of the land. But this right was distinct from the commercial lease granted to Company A. Consequently, the action for rent determination of the renewed lease could be brought by Company B, even if Company A had sued the wrong defendant.

However, note that this decision does not mean that anyone can intervene in proceedings. The intervener must have a right of their own, i.e., a personal and direct interest to act. For example, a shareholder of an SCI cannot intervene to claim rent if the SCI is the owner. But here, Company B had indeed become the owner, so it had standing to act. What few people know is that this solution has since been confirmed: the Cour de cassation has applied the same principle in other areas, such as construction law or easements. This has been settled case law since 2010.

What this means for you — practically

If you are a landlord: this decision requires you to be vigilant about the capacity of the parties in a lawsuit. If your tenant sues you, but another person (a subtenant, a buyer of the business) intervenes, do not think that the inadmissibility of the initial action ends everything. The intervener may have a right of their own and succeed. For example, in Alès, a landlord was ordered to pay arrears of rent to an intervener who had bought the business, even though the initial tenant's action was time-barred. Result: the landlord had to pay twice. undefined, I have come across cases where landlords neglected the intervention of a third party, thinking the matter was closed. Fatal mistake.

If you are a tenant or buyer of a business: this decision is a protection. If you buy a business and the seller had already started a lease renewal procedure, you can intervene to take over the action. Even if the seller made a mistake (e.g., suing the wrong owner), your intervention can save the procedure. You simply need to show that you have a right of your own, i.e., that you have become the tenant or owner of the business. However, note: you must intervene before the main action is finally adjudicated. Deadline: for commercial leases, the action for rent determination must be brought within two years of renewal (Article L. 145-57 of the Commercial Code). If you delay, you risk losing your right.

If you are a property professional (agent, notary, manager): this decision reminds you of the importance of checking the chain of rights. When selling a business, ensure that the seller has standing to act in court if proceedings are ongoing. The buyer will need to intervene voluntarily to take over the proceedings. A lack of vigilance can lead to nullity of the procedure, with serious financial consequences. For example, in Nîmes, an estate agent was ordered to compensate his client for failing to point out that the seller had a poorly brought action pending. Cost: €15,000 in damages.

Four tips to avoid this type of dispute

• Check the capacity of the parties before suing. Before starting legal proceedings, make sure you are suing the right person. If you are a tenant, check who the current owner of the premises is (via the register of co-ownership or the land registry). A simple Kbis extract of the owner can avoid an error.
• Intervene quickly if you buy a business or property during ongoing proceedings. As soon as the transfer deed is signed, inform the court of your voluntary intervention. Do not wait until the case is decided. Use a solicitor to draft intervention pleadings.
• Keep all documents proving your own right. If you intervene, you must show that you have a personal interest: deed of sale, lease contract, rent receipts, etc. Without proof, your intervention will be inadmissible.
• Consult a lawyer solicitor at the first signs of conflict. A simple letter before action can trigger proceedings. A solicitor will advise you on the strategy to adopt: act alone or intervene in an existing action. In Uzès or Alès, a local solicitor knows the practices of the commercial courts.

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

Further reading: related case law and developments

This 2010 decision is part of a line of protection for voluntary intervention. As early as 2005, the Cour de cassation held that a mortgage creditor's principal intervention was admissible even if the partition action was inadmissible (Civ. 1re, 15 March 2005, No. 02-18.127). In the same year, in agricultural leases, the Court admitted that the intervener could substitute for the defaulting main claimant (Civ. 3e, 12 July 2006). The trend is therefore clear: judges favour access to the court for persons with a legitimate interest, even if it means separating the fate of the intervention from that of the main action.

Since 2010, case law has confirmed this direction. For example, in 2018, the Cour de cassation extended this principle to easements: a neighbour may intervene to defend their right of way even if the main action is inadmissible (Civ. 3e, 22 March 2018, No. 16-26.441). In commercial law, the solution is now well established. What this means for the future: landlords must be particularly cautious when proceedings are brought by a tenant, because a third party (subtenant, buyer) can always intervene and revive the case. Courts will be increasingly inclined to examine the merits of the intervention, without being stopped by an inadmissibility of the main action.

What you absolutely must remember

1. Principal voluntary intervention is autonomous. If you have a right of your own, you can act even if the main action is inadmissible.
2. Do not neglect an intervention. If a third party intervenes in your case, do not think the matter is over because the initial action is void. The intervener may win.
3. Act quickly. To be admissible, the intervention must be made before the main action is finally decided. For commercial leases, deadlines are strict (often 2 years).
4. Prove your interest. The intervener must show they have a right of their own: ownership, lease, etc. Without proof, the intervention will be rejected.
5. Consult a solicitor. This area is technical. A procedural error can cost you your right to lease renewal or expose you to damages.

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 →