In accordance with Articles R.2113-4 to R.2113-6 of the French Public Procurement Code, the services are provided in 4 tranches defined as follows: Firm tranche: Impact study - initial state. Optional tranche 1: Preparation of files. Optional tranche 2: Additional services during the study phase. Optional tranche 3: Additional services during the works phase, ecological monitoring of compensatory measures and monitoring committee.

the services of the Firm Tranche will be performed from the date set by the service order which will prescribe the commencement of them. For Optional Tranches, the execution period will start from the date of the consolidation of the tranche in question. The consolidation of each optional tranche must be carried out from the start of the execution of the firm tranche and within the period mentioned in the deed of commitment