She was the grandaughter of Victoire de Rohan. No images of her mother, Louise Aglaé of Bouillon, can be found. A genealogical sketch of Berthe de Rohan-Guémenée can be found here.
The artist may be Horace Lecoq de Boisbaudran.
From Wikimedia; spots removed and the left side of the bottom edge fixed with Photoshop and exposure increased.
Princess Berthe wears a later pre-Victorian evening dress with a natural waistline and a bertha over almost unexpanded sleeves. Her jewels, except for the bracelets, form a matched set or parure.
Keywords: Lecoq, Berthe de Rohan-Guémenée, duchesse de Bouillon, de Rohan-Guémenée family, Princess, Duchess, French, curly coiffure, tiara, feathered hat, off shoulder scoop neckline, lace bertha, elbow length full virago sleeves, natural waistline, full skirt, necklace, earrings, brooch, braclets, fan, lace wrap