[2] The cars were initially built in small numbers for competition use, but they were exhibited and offered for road use at the 1927 Paris Motor Show.

[3] They used a front-wheel-drive system featuring Grégoire's patented Tracta constant-velocity joint and sliding pillar independent front suspension and a live axle with quarter-elliptic leaf springs at the rear.

[2] Only two of the Tractas competing in 1929 completed the race, the two-stroke experimental car retiring after 43 laps.

In 1955 Grégoire introduced an intriguing Sports Cabriolet prototype, with body by Chapron, front-drive and a 2188 cc supercharged ohv boxer engine ahead of the front wheels.

[6] It is not clear how seriously Grégoire contemplated selling the Sports Cabriolets exhibited in the 1950s, but they provided an impressive showcase for his engineering philosophy and talent.

[6] Two of the Sports Cabriolets produced turned up in October 1956 at the 43rd Paris Motor Show: one was exhibited on the Henri Chapron stand and the other on a small stand against the wall, positioned next to that of the British AC company, and the identified by the name "Grégoire (Tracta)".