Rent review of a French commercial lease

Sources and assumptions

• entreprendre.service-public.gouv.fr — F31925 — tax year 2026, verified on September 17, 2026

  Excerpt from the source : « L'augmentation du loyer à la suite du déplafonnement ne peut pas être supérieure, pour une année, à 10 % du loyer acquitté au cours de l'année précédente. On appelle cela le lissage du loyer. »

• entreprendre.service-public.gouv.fr — F31925 — tax year 2026, verified on September 17, 2026

  Excerpt from the source : « Si par le jeu de la clause d'échelle mobile, le loyer augmente ou diminue de plus d'¼ par rapport au prix précédemment fixé, l'une des parties peut demander la révision immédiate du loyer. »

Calculation assumptions

• The calculation covers a commercial lease governed by the French statute on commercial leases, reviewed during the term. A residential lease uses a different index and a different calculator; a professional lease (bail professionnel) follows its own rules; and the fixing of the rent on renewal, after nine years, is not covered here.
• You enter both index values yourself; the tool does not store them. They are quarterly, published two quarters in arrears, and the useful pair depends on the quarter stated in your lease and on how far back the previous review goes: no fixed pair would fit every lease, and any fixed pair would be out of date within three months. Read them from your review notice or from the Insee release.
• The reviewed rent is truncated down to the cent. No statute sets a rounding rule for rent: the convention used here is the one applied in the worked examples published by the administration, and you can reproduce it to the cent by redoing the division.
• Not modelled: uncapping to rental value (change in local trading factors, change of authorised activity, lease duration) and the smoothing of the resulting increase, the immediate review set by the court under a sliding-scale clause, turnover-based rent clauses, and the capped indexation clause (clause tunnel) available for leases signed or renewed since 28 May 2026. The rent calculated is the indexed rent, with no cap other than the change in the index.
• The calculation uses the monthly rent excluding service charges and taxes. Recharged charges and taxes, VAT on rent, key money (pas-de-porte) and the security deposit follow their own rules. A rent billed quarterly yields exactly the same percentage change: divide it by three to reason per month.