the seeded configuration (High order Harmonic in Gas seeding and Echo Enable Harmonic Generation) using a Conventional Linear Accelerator (CLA) of 300 MeV. The FEL beamline includes a 15 m in vacuum (potentially cryogenic) undulator of 15 and 30 mm period and is designed also in order to accommodate a Laser Wake Field Accelerator (LWFA) ranging from 0.3 to 1 GeV, relying on electron beam parameters produced and accelerated by either the 60 TW laser of LOA or by the 10 PW APOLLON laser of ILE (Institut de Lumière Extrême).