From 1969-1971, the Citroën M35 was produced. It was a prototype 2-door fastback coupe made to research the Citroën Wankel engine in normal service with paying customers who do high mileages. Only 267 M35 coupes are made out of the intended 500. Heuliez built them. Robert Opron had designed the M35 with obvious similarities to the Ami 8, but few panels were shared between the two models.