During the 1930s, they were offered as an expensive option for expensive cars, Delage, Delahaye, Salmson, Bugatti among them. As far as I can tell, North American manufacturers never used the system. A big part of the attraction must have been the avoiding of dealing with the non synchro gear change.
Post-war, they could be had on some Peugeot, (French) Ford SFA, and Citroën Traction models but they were also used on trucks, buses and even railcars.
More here, Youtube