the Empress of the French

judging by the date of the frame, this must be the wife of Napoleon III, emperor of France 1852-1870

as discussed by Walker, 1853 was the year of Louis Napoleon’s marriage to Eugénie, daughter of an impoverished Spanish nobleman; echoing themes of the novel, not only was this a rags-to-riches story for Eugénie but there were doubts as to whether Napoleon III was the son of his father, Louis Bonaparte (brother of Napoleon I); a good summary is available on the Boys’ historical clothing website (of all uinlikely places!)