When a contract is concluded at a firm price in application of article R. 2112-10, its clauses specify:
1° That this price will be updated if a period of more than three months elapses between the date on which the tenderer set its price in the tender and the date on which performance of the services begins;
2° That the update will be made under economic conditions corresponding to a date three months prior to the date on which performance of the services begins.