In May '62, while filming, Jeanne Moreau suffered a slight nervous breakdown due to the stifling atmosphere of the film.
Orson Welles reportedly dubbed a few lines of Anthony Perkins dialog. Perkins later said he could never figure out which lines they were.
Orson Welles told Peter Bogdanovich in "This Is Orson Welles" that "there's not a single symbol" in "The Trial".
When the film came out, Orson Welles called this his best movie. Later, he picked "Chimes at Midnight (1965)."