SOMECA (La Société de Mécanique de la Seine) was a subsidiary of the French automobile manufacturer SIMCA. It originated in the 1950s when it acquired MAP and its two-stroke diesel engine. Fiat held a majority stake in SOMECA, and by the 1960s, the model lineup was integrated with Fiat. In 1983, SOMECA ceased to exist as an independent brand and was completely merged into FiatAgri.