William Dieterle had full charge as director for about a week because of a breach-of-contract suit filed against Max Reinhardt by a French film company. The judge found in favor of Reinhardt, and lifted the restraining order.
When the forest that Max Reinhardt designed could not be lit properly, cinematographer Hal Mohr thinned the trees slightly, sprayed them with aluminum paint and covered them with cobwebs and tiny metal particles to reflect the light. As a result, he became the first (and only) write-in winner of an Academy Award.
Composer Erich Wolfgang Korngold was personally chosen by director Max Reinhardt. Both agreed in an early production stage to use the original incidental music written by Felix Mendelssohn-Bartholdy as the film's soundtrack. (Reinhardt did a stage production of the play before and used Mendelssohn's music.) As the film runs over two hours it was obvious that Mendelssohn's composition would be too short. Instead of just repeating several musical cues to fit the film's final length Korngold adapted the incidental music and parts of some other compositions by Mendelssohn, re-orchestrated them for a larger orchestra and choir (most notably heard in his Wedding March version at the end) and composed some short musical bridges by himself. Thus he created a complete symphonic score for the movie based on Mendelssohn's music. However, he chose to remain uncredited as a composer and insisted on giving full musical credit to Mendelssohn.
James Cagney's daughter, Cathleen Cagney, has said when she was a child and saw this movie, she was so upset by the scene where her father is turned into a donkey, that they had to bring James out to calm her down.