Which 1929 musical was Ernst Lubitsch’s first sound film?

Ernst Lubitsch’s first sound film was the 1929 musical The Love Parade.1

In this inventive operetta, Maurice Chevalier and Jeanette MacDonald—in her film debut—portray a romance set in the mythical land of Sylvania. The film was notable for Lubitsch's innovative approach to the transition to sound; he freed the camera from the static positions and soundproof boxes that limited many other directors of the era, often filming sequences without dialogue and dubbing the sound in later. The Love Parade was nominated for an Academy Award for best picture, and Lubitsch received a nomination for best director.1