As with a residential lease, it is usual to provide that the rent for a commercial lease(Sheet 20-5: The Commercial Lease) or a professional lease (Sheet 20-2:The Professional Lease) is increased each year according to the variation of an index.

The cost of construction index can always be used in a commercial or professional lease.
The parties may choose another index. Attention, it is forbidden to use for the indexation :

• - the SMIC (Minimum Interprofessional Growth Wage),
• - the general level of prices or wages,
• - the prices of goods, products or services that do not have a direct relationship with the object of the lease or with the activity of one of the parties.

Recently, two new indices have been created:

• - the ILC (Indice des Loyers Commerciaux), which can be used for commercial or craft activities, with the exception of logistics warehouses,
• - the ILAT (Indice des Loyers des Activités du Tertiaire), for professional activities, logistics warehouses and activities that are neither commercial nor artisanal.

Depending on the tenant's activity, it is possible to choose between the ICC, the ILC or the ILAT. These 3 indices are published by INSEE.

Note: the rent of a commercial lease may also be revised every three years, according to the ILC or ILAT indexes, depending on the date the lease was signed.