I encountered these images in www.marcelproust.it/ while researching "Princess Soutzo" to find information about this 1889 portrait. She married a Prince and had a long affair with Paul Morand. According to a biographical sketch about her in theesotericcuriousa, Paul Morand later became a Vichy sympathizer. That article described her as "small, cute, smart and rich" and "...Rigid of character, and considered not very nice ... a force to be reckoned with..."
The columnar skirt with train, the over hanging bodice, and sheer sleeves mark these as pre-war portraits.
Keywords: Nadar, Hélène Chrissoveloni, Princess, French, bouffant coiffure, tiara, braided bun, square neckline, quarter length flared sleeves, over hanging bodice, natural waistline, tight skirt, train