LOS ANGELES — The dark tale begins with a concert violinist infatuated with a young student and ends with blackmail and suicide. In between there are visits to bars and brothels, brawls in swanky digs, creepy shakedowns and a cameo by Oscar Wilde. It sounds like a slightly experimental indie project. In reality, the movie, “Different From the Others,” opened in the summer of 1919 to sold-out houses across Germany.

The cast of this silent film, which was directed by Richard Oswald, included two up-and-coming actors: Conrad Veidt, who would later appear in “The Cabinet of Dr. Caligari” and “Casablanca,” and Reinhold Schunzel, an evil Nazi conspirator in Alfred Hitchcock’s 1946 thriller, “Notorious.”

But as much as some critics and audiences took to the film, others found it indecent, unwatchable. There were catcalls at some screenings; at others, riots and walkouts. It wasn’t just that the two romantic leads were men. The film also had the audacity to claim that homophobia, not homosexuality, was a scourge of society. The following year, censors banned “Different From the Others” throughout Germany, claiming that the film could endanger public safety or turn impressionable youths gay. When the Nazis came to power, they destroyed every copy they could find. In doing so, what many consider the world’s first feature film to showcase sympathetic gay characters and themes was lost....