1948 Act: Conventional Rent Indexation Prohibited by the Court of Cassation

Imagine: you own a flat in Marseille, in the historic district of Le Panier. The tenant has been living there for 30 years under the 1948 Act. You want to revise the rent in line with inflation, as provided for in your contract. But the tenant refuses, arguing that the 1948 Act prohibits any indexation. Who is right? The question has divided landlords and tenants for decades. The Court of Cassation ruled decisively in a judgment of 5 November 2015: the rules of the 1948 Act are matters of public policy and exclude any conventional indexation clause. An analysis of a decision that changes the situation for thousands of leases.

The facts: a story that happens every day

Mr Y, owner of a house with mixed use (residential and professional) in Marseille, let the dwelling to Mr and Mrs Z. The property, subject to the Act of 1 September 1948, comprised habitable rooms, a kitchen, and professional rooms. The tenancy agreement contained a clause indexing the rent to the construction cost index. For several years, Mr Y applied this indexation, regularly increasing the rent. But Mr and Mrs Z challenged this: according to them, the 1948 Act lays down a strict method for calculating rent, which cannot be altered by a contractual clause. The landlord brought the matter before the Tribunal d'instance of Marseille, which ruled in his favour. The tenants appealed. The Cour d'appel of Aix-en-Provence upheld the judgment. The case then went up to the Court of Cassation. It quashed the appeal judgment, holding that the lower courts had not drawn the legal consequences from their findings: the 1948 Act prevails over the parties' intention.

The reasoning of the court — analysed

The Court of Cassation relies on Article 1 of Act n°48-1360 of 1 September 1948, which provides that rents for residential premises are fixed by mandatory provisions of public policy. In practical terms, this means that landlord and tenant cannot freely decide the amount of rent: the law imposes imperative rules. Article 27 of the same Act specifies that the rent is determined according to the corrected floor area (surface corrigée), with a ceiling. However, the indexation clause inserted in Mr Y and Mrs Z's lease allowed the rent to vary according to an index, thereby circumventing the legal method of fixing rent. The High Court reminds that a clause contrary to a rule of public policy is deemed unwritten. In this case, the lower courts had noted the existence of the indexation clause but had not sanctioned its nullity. The Court of Cassation therefore censures the appeal judgment. This is a classic application of the principle of primacy of law over contract: the parties cannot derogate from the protective rules for tenants provided by the 1948 Act. No change here: the solution has been constant for decades, but it is often unknown to landlords.

What this means for you — in practice

For landlord lessors: if you own a dwelling subject to the 1948 Act, any indexation clause is void. You cannot increase the rent in line with inflation or an index. The only increase possible is that provided by law, based on the corrected floor area and triennial reviews. Example: in Vitrolles, a landlord tried to apply a 2% annual indexation to a rent of €300. After 5 years, the tenant claimed reimbursement of the overpayment, i.e. €30 per month for 60 months = €1,800. The court ruled in his favour. For tenants: you can challenge any increase based on an indexation clause. If you have paid undue sums, you can claim their reimbursement within the five-year limitation period. For purchasers: before buying a property under the 1948 Act, check the rent history. A landlord who has applied unlawful indexation may be ordered to repay years of increases. For real estate professionals: when drafting leases, never insert an indexation clause for 1948 Act dwellings. Use only the statutory revisions.

Four tips to avoid this type of dispute

• Check the status of the dwelling: before signing a lease or increasing the rent, ensure that the property is not subject to the 1948 Act. Consult the leasehold regulations or the deed of sale. Dwellings built before 1948 in certain municipalities may be affected.
• Do not use an indexation clause: even if the contract provides for indexation, it is void by operation of law. Prefer a triennial review clause in accordance with the law (increase limited to the variation of the reference rent index, but subject to the 1948 ceilings).
• Keep all supporting documents: retain rent receipts, corrected floor area calculations, and correspondence with the tenant. In the event of a dispute, these documents will help reconstruct the history.
• Consult a specialist lawyer: if you have any doubt about the validity of an increase or if a conflict arises, seek advice before acting. A mistake can cost several years of reimbursement.

Further information: related case law and developments

The position of the Court of Cassation is constant. In a judgment of 10 January 2007 (n°05-18.307), it had already held that the rules of the 1948 Act are matters of public policy and that any contrary clause is void. More recently, a judgment of 13 February 2020 (n°18-24.654) specified that even an indexation clause accepted by the tenant for years remains void, because public policy cannot be covered by confirmation. The trend is therefore clear: the courts protect the tenant against any conventional increase. In future, it can be expected that judges will increasingly penalise landlords who try to circumvent the law. The only possible change would be legislative, but the legislature has not amended the 1948 Act since its creation. For leases concluded after 1948, the Act has been repealed, but for existing leases, it remains applicable indefinitely.

Summary and next steps

FAQ:

• Can I increase the rent for a 1948 Act dwelling? Yes, but only according to the legal rules (triennial revision based on corrected floor area, within the ceiling limits). No free indexation.
• What if I have paid indexed increases? You can claim reimbursement of sums paid within the last 5 years (limitation period). Send a registered letter to the landlord, then apply to the court.
• My lease contains an indexation clause, is it valid? No, it is deemed unwritten. You can apply to have it annulled in court.
• Can a landlord recover the increases not received? No, because the clause is void. He cannot demand a rent higher than that fixed by law.

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