Tissot was a renowned painter of gorgeous and gorgeously-dressed women. He spent 1871 to 1882 in the UK; this was probably painted after he returned from the UK.
From Wikimedia.
Clotilde poses seductively wearing a sheer top with a high neckline and long sleeves under a one shoulder over-dress.
Keywords: Tissot, Jeanne Marie Clotilde Briatte, Clothilde Briat, comtesse Pillet-Will, Briatte family, Pillet-Will family, Countess, French, straight coiffure, bangs, chignon, hair band, chemisette, high enclosing neckline, necklace, long close sleeves, buttoned cuffs, bracelets, over-dress, one arm neckline, natural waistline, waist band, close skirt