[en] This article proposes an overview of activities as those performed by the LEA (a laboratory of activity calibration) which produces and distributes radioactive sources which are daily used in nuclear medicine departments, nuclear installations, analytical laboratories, and research centres. It more particularly emphasizes that this activity is a unique French know-how which is a heritage of the CEA, is a specific activity which is submitted to many operational, regulatory and standard requirements. It also outlines the technicity and adaptability of the laboratory in providing specific solutions for specific calibration contexts. It finally evokes the collaboration with Framatome in EPR projects (fabrication of primary rods or primary neutron sources)