| Compagnie Electro-Mecanique | |
| Type: | Subsidiary |
| Industry: | Rail transport |
| Successor: | Alstom |
| Defunct: | 1983 |
| Location: | Lyon, France |
| Area Served: | Worldwide |
| Products: | Locomotives High-speed trains Intercity and commuter trains Trams People movers Signalling systems |
Compagnie Électro-Mécanique (CEM) was a French electrical engineering manufacturer based in Paris, Le Havre, Lyon, Le Bourget, Nancy, Dijon. It was a subsidiary company of Brown, Boveri & Cie.
The company produced DC motors, AC motors, generators, turbines, transformers and railway locomotives. Examples of railway locomotives included SNCF Class C 61000 and SNCF Class CC 65500.
It was acquired by Alsthom in 1983.