Facing the constant rise in the cost of living in France, housing remains at the heart of concerns for both tenants and landlords. The Indice de Référence des Loyers (IRL / Rent Reference Index), published quarterly by the INSEE (French National Institute of Statistics and Economic Studies), is the only legal tool allowed to regulate and revise the rent amount during an ongoing lease. Understanding how it works, mastering the calculation rules, and knowing the exceptional capping mechanisms is essential to secure your rental relationships and avoid disputes. Whether you are a landlord wishing to maintain the value of your property or a tenant eager to have your rights respected, this comprehensive guide provides you with all the legal keys to master the IRL index.
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The Indice de Référence des Loyers (IRL) is the official indicator used as the basis for revising rents for unfurnished or furnished properties rented as a primary residence. Created to protect tenants' purchasing power while allowing landlords to cope with inflation, it is calculated based on the average, over the last twelve months, of the evolution of consumer prices excluding tobacco and housing rents.
Rent revision is not automatic: it must be expressly provided for by a clause in the tenancy agreement, known as a clause d'indexation (indexation clause) or clause de révision (revision clause).
The legal framework for this revision is strictly defined by:
If the lease does not contain any revision clause, the rent must remain identical throughout the entire duration of the tenancy, except in very specific cases of improvement works or if the rent is manifestly undervalued at the time of lease renewal.
To cope with historic inflation, the French legislature introduced a temporary capping mechanism on the increase of the IRL, commonly known as the bouclier loyer (rent shield). Established by Law No. 2022-1158 of August 16, 2022 on emergency measures to protect purchasing power, this mechanism capped the annual increase of the IRL at 3.5% in metropolitan France.
Initially scheduled to apply until June 30, 2023, this cap was extended by Law No. 2023-568 of July 7, 2023 until the 1st or 2nd quarter of 2024 (depending on publication dates, phasing out definitively in the first half of 2024). Different rates applied in overseas territories (2.5%) and in Corsica (2% or 3.5% depending on prefectoral decree). Since the end of this mechanism, the IRL has returned to its classic calculation method based on real inflation, making vigilance regarding the figures published by the INSEE even more crucial.
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For a landlord to legally increase the rent during a lease based on the IRL, several cumulative conditions must be met.
The lease agreement must imperatively mention the possibility of an annual rent revision. This clause must specify the reference quarter of the IRL to be used. In the absence of details in the lease, the law states that the quarter to be used is the one corresponding to the latest index published by the INSEE on the date the lease was signed.
The revision can only take place once a year, on the date agreed upon in the lease or, failing that, on the anniversary date of the tenant's entry into the premises.
This is a major restriction resulting from Law No. 2021-1104 of August 22, 2021 on combating climate change and strengthening resilience to its effects.
Since August 24, 2022, any rent revision is strictly forbidden for properties classified as passoires thermiques (energy sieves), meaning those graded F or G on the Diagnostic de Performance Énergétique (DPE / Energy Performance Certificate). This ban applies in metropolitan France to rental contracts concluded, renewed, or tacitly extended since that date. If your accommodation is graded F or G, the rent is frozen, regardless of the presence of an indexation clause in the lease.
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The rent revision calculation follows a precise and legal mathematical formula. To perform this calculation, you must have three elements:
$$\text{New Rent} = \frac{\text{Current rent excluding charges} \times \text{New IRL}}{\text{Old IRL}}$$
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Let's take the example of Marie, who rents an unfurnished apartment in Lyon for a rent of 900 € excluding charges. Her lease was signed on October 15, 2022. The indexation clause provides for an annual revision based on the IRL of the 2nd quarter.
The calculation is as follows:
$$\text{New Rent} = \frac{900 \times 145.17}{140.59} = 929.28 \text{ €}$$
Marie's new rent excluding charges is therefore set at 929.28 € per month, representing a monthly increase of 29.28 €.
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Now let's imagine Pierre, a tenant in a studio in Paris with a rent of 650 € excluding charges. His lease revision takes place in the 1st quarter of 2023, right in the middle of the application period of the bouclier loyer (capped at 3.5%).
Without the shield, inflation could have pushed the index much higher. Thanks to the legal capping of the IRL increase at 3.5%:
The simplified calculation is as follows:
$$\text{Maximum New Rent} = 650 \times \left(1 + \frac{3.5}{100}\right) = 672.75 \text{ €}$$
Pierre's landlord could not demand a rent higher than 672.75 € excluding charges.
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Since the rent revision is not automatic, the landlord must follow a strict procedure and formal requirements for the increase to be enforceable against the tenant.
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[Step 1: Verification of the DPE rating (A to E)]
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[Step 2: Calculation of the rent via the IRL formula]
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[Step 3: Written notification to the tenant]
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[Step 4: Application at the end of the notice period]
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Before taking any steps, the landlord must ensure that the property is not an energy sieve (DPE graded F or G). They must also check for the presence of the indexation clause in the tenancy agreement.
The landlord must consult the official INSEE website to obtain the exact values of the IRL corresponding to the quarter mentioned in the lease.
The landlord must inform the tenant of the rent revision by lettre recommandée avec accusé de réception (LRAR / registered letter with acknowledgement of receipt) or by hand delivery against a signed receipt. This letter must obligatorily mention:
Since the Alur Law of March 24, 2014, the landlord has a period of one year from the revision date to make the request to the tenant.
Please note: the revision is not retroactive. If the landlord waits several months before notifying the tenant, the increase will only take effect from the date of the written notification. The past months without revision are definitively lost for the landlord.
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No, if the lease contains a valid indexation clause, the property is not graded F or G, and the calculation strictly respects the index published by the INSEE, the tenant cannot object to the increase. It is legally binding.
The tenant must immediately send a registered letter with acknowledgement of receipt to their landlord to dispute the calculation, providing the correct calculation based on the official INSEE indices. If the dispute persists, it is possible to refer the matter to the Commission Départementale de Conciliation (CDC / Departmental Conciliation Commission).
The Diagnostic de Performance Énergétique (DPE) must obligatorily be attached to the lease agreement when it is signed. If the DPE has expired (validity of 10 years) or is missing, the tenant can demand that the landlord carry out a new diagnostic at their own expense.
No. The IRL only concerns residential leases used as a primary residence. For commercial leases, the Indice des Loyers Commerciaux (ILC / Commercial Rent Index) or the Indice des Activités Tertiaires (ILAT / Tertiary Activities Index) is used. For professional leases, the Indice du Coût de la Construction (ICC / Construction Cost Index) or the ILAT applies.
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Legal information for guidance only, not personalised legal advice. For your specific situation, ask your question free of charge on AvocatAI — answers based on French law, in your language.