The claw rotor (2) comprises: an axial symmetry axis (X-X); two magnet wheels having a core and teeth (9); insulation (11′) for a field coil (10) mounted onto the core; and permanent magnets mounted between two adjacent teeth (9) belonging to one and the other of the magnet wheels, wherein the insulation (11′) comprises a hub and a flange on each end of the hub (110), each flange having a plurality of projecting petals for engaging with the angled inner periphery (90) of a tooth (9). At least some petals of a flange (120) corresponding to the permanent magnets (38) are split into a plurality of portions, namely, a main petal (121a) for engaging with the inner periphery (90) of a tooth of the magnet wheel (8) in question and at least one side secondary petal (121b) that is lower, when seen in the radial direction, than the main petal. The rotating electrical machine comprises such a rotor. The invention is of use in a claw rotor for motor vehicle alternator or alterno-starter.