This is a commonly available image of her. The fullness and height of the Empress Eugenie's dress is enhanced in the back giving a bustle-lime effect in this 1864 Mayer portrait.
From the LIFE magazine archives; sepia tone removed by gogm.
Her sleeve cuffs with tassels have a mountain man or frontier scout look.
Keywords: 1865, Mayer, Empress Eugenie, Empress, Bonaparte family, French, straight coiffure, feathered hat, high neckline, collar, bows, long close sleeves, crinoline