Mark Sandrich, who directed five of the Fred Astaire-Ginger Rogers musicals, was a physicist before he got into filmmaking. He would devise blueprints for every scene so he would know exactly where to put the cameras and the actors.
The finale of "Top Hat, White Tie and Tails" production number with Fred Astaire miming his cane as a weapon "attacking" his supporting dancers, 13 canes were prepared for it. During shooting, Astaire, ever the unforgiving perfectionist, was continually breaking his canes in frustration at his mistakes, which concerned the crew that he was running out of them. As it turns out, the shooting of the scene was finished with the very last cane.
The Venice canal set was so large it required two adjoining sound stages at RKO's Gower studio. The entire length was over 300 feet. Up to that time, it was the largest set ever built on the RKO lot.
Erik Rhodes's Italian characterization so offended the Italian government - and dictator Benito Mussolini in particular - that the film was banned in Italy. The same fate had befallen Cerco il mio amore (1934) the year before.