Article L2392-5 of the French Public procurement code
A pooled solution, made available by the State and known as the “public invoicing portal”, enables invoices to be submitted, received and transmitted electronically. The following shall use the public invoicing portal to implement the obligations laid down in sub-section 1 of this section: 1° The State and its public establishments; 2° Holders of defence or security contracts concluded with a purchaser mentioned in 1°, as well as their subcontractors…