I Don't Know You and I Love You.

The operetta composer Robert Ottmar is fascinated when he discovers a picture of a young lady in a newspaper. The beauty's mere countenance inspires him to write a new operetta, which is very successful. Ottmar learns that his beloved is called Gloria and is the daughter of a general manager from Nice. In order to find out whether Gloria corresponds to his ideal image in reality, he hires himself out as a valet in her father's villa - incognito, of course.