Marie is left alone. She thinks money and position are meaningless (""Par le rang et l'opulence""). She hears soldiers marching in the distance. She is delighted when the whole regiment files into the room. She leads them in singing a patriotic tribute (""Salut à la France""). Marie is reunited with Tonio. Tonio asks for Marie's hand in marriage. The Marquise is unmoved by the young man's declaration that Marie is his whole life (""Pour me rapprocher de Marie""). She says her niece is engaged to another man. She dismisses Tonio. The Marquise and Sulpice are left alon. She confesses the truth: Marie is her illegitimate daughter. She abandoned Marie long ago, fearing social disgrace.