The ILC and the indexation of a French commercial lease

The commercial rent index (indice des loyers commerciaux, ILC) is the Insee index used to adjust the rent of premises let for commercial or craft activities under a French commercial lease (bail commercial). Its latest value is 137.16 for Q2 2026, published in the Journal officiel on 25 September 2026. That is 0.26% above the same quarter a year earlier and 4.06% above the same quarter three years earlier. The two figures matter because a commercial lease can move in two ways. By law, either party may ask for a review every three years, under articles L145-37 and L145-38 of the Commercial Code, and the variation of the index over those three years is the usual reference. Many leases also contain a sliding-scale clause (clause d’échelle mobile) that indexes the rent automatically every year on the quarter they name. The calculator applies the ratio of two ILC values to the annual rent before VAT and shows the monthly equivalent.