Her Wikipedia article is here. She was a direct descendant of Hortense Mancini and she bore her first husband, Prince Honoré IV of Monaco, two sons who both had a chance to rule Monaco. She also bore two illegitimate daughters. Their marriage ended in divorce in 1798. She was a Duchess suo jure.
This is probably excerpted from the next image that lists the artist and location.
From the lost gallery's photostream on flickr. Also posted to the Reign of Louis XVI 1775-1789 Album here.