After completing one scene in the role of Franz Roberti, Francis Lederer refused to shoot a particular set-up, complaining it showed his "bad" side. Katharine Hepburn and assistant director Edward Killy complained to studio head J.P. MacDonald, who fired Lederer and replaced him with Charles Boyer.
The character of Franz Roberti was based on two real-life conductors of the period: Leopold Stokowski, who was well known for his rearrangements of music by Bach, Wagner and other composers; and Arturo Toscanini, who was notorious for insulting his musicians during rehearsals the way Roberti does in the film.