Rental revision, IRL or ICC?

How to revise the rent?

The current French official rental referencing index (indice de référence des loyers) has been published on january 13, 2012 by INSEE*.
As long as it is mentionned on the lease contract, the rental amount can be revised each year, based on the IRL (indice de référence des loyers - rental referencing index) which is published each trimester by INSEE*.
Revision date: anniversary date of lease
The following formula enables you to calculate the new amount of the rent :

Current rent x new IRL known at revision date
IRL known at date of lease or at date of last revision

The last average of ICC (Indice du Coût de la Construction / Index for Building Cost) was published by the INSEE (French National Institute for Statistics and economics Studies) on january 8, 2012.
The history of the ICC is available for consultation and downloadable on the site of the INSEE: Index for Building Cost