An international collaboration, involving the Astrophysics Department-AIM Laboratory of CEA-IRFU, managed to determine, from asteroseismology, that up to 65% of stars more massive than the Sun (between 1.6 and 2 solar masses) have a very high internal magnetic field. So far, only 5-10% of these stars were suspected to have a magnetic field up to 10 million times that of Earth.