The Tertiary Activities Rent Index (TARI) consists of a weighted sum of indices representing the levels of consumer prices, prices of new dwellings and gross domestic product.
- The representative index of the consumer price index excluding tobacco and housing rents, for households in Metropolitan France and the overseas departments (IPCL) published by Insee.
- The index representing the price level of new constructions is the "Cost of Construction Index" (ICC) published by Insee.
- The index representing the Gross domestic product is constituted by the quarterly gross domestic product in value adjusted for seasonal and working days (MoyPIB) published by Insee.
Each of the indices composing the TARI is calculated as a mean :
- over 12 consecutive months for consumer prices, which is a monthly index (mIPCL);
- over 4 consecutive quarters for the cost of construction index and gross domestic product in value which are quarterly (mICC and mPIB).
To calculate these means, the last month (or quarter) taken into consideration corresponds to the last month of the quarter (or to the quarter) for which the TARI is being calculated. Each of the means calculated in this way and the TARI itself are expressed in relation to a reference of 100 in the first quarter of 2010.
The three indices contribute to the calculation of the TARI according to the following weighting:
tertiary activities rent index (TARI) = 50% mIPCL + 25% mICC + 25% mPIB.
Decree n°2011-2028 of December 29, 2011 sets out the firms concerned and the procedures for calculating and publishing the index.
According to the Law 2014-626 of June 18th, 2014 (article 9) which modifies it, and the article L145-34 of the commercial law by resulting, two indicators can be used for the revision of the professional leases: the commercial rents index and the tertiary activities rent index.