At the moment, there is only one superconductor likely to succeed niobium-titanium (NbTi) in the medium term for large-scale applications that need electromagnets using high current densities in high magnetic fields (in excess of 12 teslas). This is the intermetallic compound of niobium-tin (Nb3Sn). The research and development programme, carried out jointly with CEA and Alstom/MSA, has as objective the acquisition and advancement of Nb3Sn technology for the management of projects involving new superconducting magnets with very high fields. Three key operations have been carried out in parallel: development of Nb3Sn wires displaying very high performance characteristics, fabrication of a quadrupole magnet model, and development of ceramic-type electrical insulation.