[en] The emergency situations for nuclear materials in the relevant facilities are provided for in the French regulation. Indeed, a decree dated May 1981, related to the protection and control of nuclear materials, specifies that 'In any circumstance, the Ministry in charge of industry can order a physical inventory of the materials and its comparison with the accountancy records'. These inventories can be required in nuclear facilities, for example in case of a suspicion of nuclear materials theft, loss or diversion. In such situations, operators must be able to check if all nuclear materials held are really inside the perimeter of the facility and in the expected locations. In order to test the organization nine exercises of increasing complexity have already been carried out involving both the concerned operators, the competent authority and its technical support body (IRSN). These exercises have allowed the validation of the methodology as well as the relationships between the multiple crisis centers or the relations with different entities involved for carrying out an inventory in case of emergency. After a short overview of the French domestic regulation, this paper describes various aspects of exercises of nuclear materials inventory in case of emergency, the methodology used and the feedback of these exercises. (author)