Spécialités Sova was a company based in Thonon-les-Bains, a town on the south bank of Lac Léman (Lake Geneva to you and me) 35 km east of Geneva. Slightly surprisingly, as you go east along the south bank of Lac Léman you come to France.
The speciality of Spécialités Sova was the precision casting of bronze and aluminium. It was particularly famous for its brake calipers and for its wing nuts (a particular fetish object of cyclists from the 1930s to the 1950s).
During the late 1930s and the 1940s Sove manufactured a number of derailleurs. I know of at least three models - but have relatively little information about them.