According to Wikipedia, the Soutzos family dates back to the time of Emperor Constantine making them Byzanto-Greek. From what I can find, the sitter may be Hélène Jean Soutzo, born in 1854. It is not Hélène Chrissoveleni who was born in 1879. This Princess Soutzo looks to be a handsome 33-year Lady posing in repose.
From Wikimedia; the image was dominated by reds and yellows so I adjusted the colors with Photoshop to make the largest flower behind her white and enhance the green of the foliage. The jar on left side of the table looks like pewter here, but it looked like gold in the original.