From Rocklopedia Fakebandica
Jonny spielt auf by Ernst Krenek. This titillating slice of modernity was held up by the Nazis as a prime example of "degenerate art."
Jonny is a vulgar anti-hero who steals a violin from Daniello, and makes unwanted sexual advances on opera singer Anita. Its a sort of metaphoric conflict between European classical music and modern American Jazz.