After the M63 Jean Rédélé developped the M64 for the 1964 season. It was initially available in two versions, one with a 1149cc engine and the other with a 1001cc engine (the latter because l'ACO had outlawed cars with engines smaller than 1 litre for 1964). Later in 1965 a 1296cc engine would be available.
It won its class in the 1964 24h of Le Mans. The following year a special prototype with olepneumatic suspension (not related to Citroën's system) was tested, but unfortunately the car was destroyed in a crash while testing.