Article R2393-41 of the French Public procurement code
The purchaser may require the holder to accept all or some of the subcontractors who are not subcontractors. It shall state this in the invitation to tender.In this case, these subcontractors shall be accepted under the conditions laid down in this section.The purchaser shall specify, where appropriate, the parts of the contract services or the amount of the subcontract above which the subcontractor, if any, must be accepted.