In 1792, Catherine Hubscher, a laundry maid, saved, with the assistance of her betrothed, Sergeant Lefebvre, a noble Austrian, Count Neipperg. The years pass and Lefebvre becomes the Marshal of France and Duke of Dantzig. He has married Catherine, nicknamed Madame Sans-Gêne because of her frankness and earthy language. All the characters – and Napoleon – are mixed up in a court intrigue for which the Emperess and Neipperg will pay the price. Well advised by her friend, Fouche, Catherine victoriously resolves the imbroglio.