I am currently reading the book Tender Comrades: A Backstory of the Hollywood Blacklist edited by Patrick McGilligan and Paul Buhle (St. Martin's Press, 1997), which features interviews with many Hollywood figures whose careers were touched by the House Un-American Activities Committee (HUAC) investigations in the late '40s and '50s. Director Jules Dassin (Thieves' Highway, Rififi, Night and the City, Never on Sunday) was interviewed by film historian Patrick McGilligan for this collection.
In the book, McGilligan asked Dassin about his first cinematic efforts, most of which the director dismissed as "hopelessly superficial." After arriving in Hollywood in the early 1940s after experience with The Federal Theatre and Artef, a Yiddish theater group in New York, Jules Dassin was hired by Metro-Goldwyn-Mayer. The contrast between his former working conditions and that at the "Tiffany of movie studios" could not have been more dramatic.
The first film that Dassin was assigned to was a B movie that was a propaganda piece about a pair of identical twin brothers, one of whom, Baron Hugo Von Detner, was a prominent Nazi in the diplomatic service in the U.S. just before the war. The other brother was a gentle bibliophile called Otto Becker, who had left Germany when the Nazis came into power and became an American citizen. The "good" brother is content with running a small antique book store and sharing his quarters above the shop with a sweet-voiced canary--who, significantly, stops singing one evening.