Bolwieser (1977)

A woman destroys her civil-servant husban by adultery during Hitler's rise in Germany.

From memory: Congenial adaptation of the Oskar Maria Graf novel meticulously dissects petty bourgeois society and ideology at a time just before the Nazi takeover of the country; an intense melodrama with excellent cast from Fassbinder's actors troupe. 

Maltin**1/2: "Studied, stylized look...Some telling moments, and fine performances, but awfully slow going."