The BT01 Index is France’s national construction index (all trades).
It measures changes in the cost of factors of production in the building industry and is the official reference for updating and revising construction contract prices.
The Index was created by a decree published in the Official Journal on December 20, 2014 (base 100 = 2010 average) and is published monthly by INSEE. It thus succeeds the Index of Building and Public Works (bases 1974 and 1975), which has been discontinued.
Below are the values of the Index by year with the changes compared to the previous month, the beginning of the year, over 12 months, and over 24 months:
Use of the BT01 Index:
The price of the contract of services will be revised at each expiry of the agreement according to a formula that integrates the evolution of the BT01 Index.
[New price] = [old price] X [Known reference index BT01] / [Reference index BT01]
Attention, do not confuse the BT01 Index with the “Construction Index” or the “Rent Reference Index” used to revise rents for private individuals and leases for professionals.