Al Jolson insisted on singing the opening number Vive la France live on set, as he claimed it would be impossible to do the song justice if was filmed miming to playback, in order to deliver it with the excitement and verve that only he could bring to it. Even though this presented considerable technical problems, Warner Brothers agreed (that's the real studio orchestra actually on set playing the house band of the Wonder Bar) and this is one of the very last musical numbers to be performed live on camera.
As an example of the confusion between the corporate identities of Warner Bros. and First National (the studio created by theatre owners which Warners had taken over in 1928 to acquire its theatre chains), the credits of "Wonder Bar" identify the film as a First National production, but the original trailer (included as a bonus item on the Warner Archive DVD) identifies it as a Warner Bros. production.
One scene gave the censors some consternation: A man asks a couple if he can cut into their dance, and while the woman says, "Sure!" and rushes towards him, he dances away with her partner. Upon hearing this, Al Jolson says with a twinkle in his eye: "Boys will be boys!" Warner Brothers refused to cut the scene (and it exists today in the Turner Classic Movies print). At the time, the Production Code was not rigorously enforced. Surprisingly, however, the movie was approved for reissue in 1936 despite this homosexual scene and the fact that someone gets away with murder, both clear violations of the Production Code.