Located at Bievres and derived from CMR, the company born after the World War II. CEMEC was a French company which produced motorcycles from 1948 to 1958. CMRM, the short version of Centre de Montage et de Réparation, was a French institution created in order to take care of the motorcycles "abandoned" by the German army in WW2.

　　From 1945 on, another association, CEMEC, which means "center for study of explosion motors", was founded. Its main objective was to make sure, that all the useful remainders can be useful for the French police.

　　The only model of the company was the L7. This 750cc bike, cloned 1500 times, was manufactured from 1948 to 1954, when the company closed the doors. One year later, in 1955, CEMEC was purchased by Ratier, an aircraft components manufacturer from Montrouge.

　　This manufacturer was known for its 746cc car, built from 1926 until 1930 and for its motorcycles produced from 1959 until 1962, after having taken over the business of the Centre d'Études de Moteurs à Explosion et à Combustion (CEMEC).

　　The engines were flat-twins, having the Second Wold War II BMW R12 designs as source of inspiration. The only model of the company knew eight releases, L7-1 to L7-8. Ratier continued the line of motorcycles with a 600 cc series C6S, under their own label, this model having the platform of the C8.

　　The C6S, which could reach a top speed of 160 km/h, thanks to its 32 HP, was appreciated by De Gaulle, who didn't want German bikes around him. Later on, Ratier was taken over by Thomson CSF, a major electronics and defense contractor, at the end of the '60s, this company launching the production under Ratier badge. They had another attempt to introduce a new model, but in 1962, the efforts were useless, so they focused on the production of micro-electronics for Mirage warplane. The CEMEC adventure ended here and nobody intended to re-open the book ever since.