[en] The analysis conducted within the Dossier 2005 exercise (ANDRA 2005b) shows that in all envisioned situations (normal or altered) through complementary indicators, the repository and surrounding host rock fulfill the three major safety functions, without relying excessively on any single component no elements that jeopardize the technical feasibility. In any event, the Callovo- Oxfordian host rock plays a major role in immobilizing radionuclides and in delaying and reducing their migration to the environment. In all scenarios even accidental or altered the repository performance provides significant margins to the dose objective recommended by the RFS III.2.f. In conclusion, Dossier 2005 Argile supports, with both qualitative and quantitative arguments as results from a robust methodology and a multidisciplinary iterative process, the feasibility of a reversible and safe repository in Meuse-Haute-Marne Callovo-Oxfordian clay. Some key design features and orientations have been developed to meet safety requirements. The various reviews of the ANDRA Dossier Argile that was published in 2005 and the existing design experience has helped to identify the key areas needing further development and design evolution in order to apply for a license to build a repository in 2015 according to the new French Act of 2006. (A.L.B.)