Adélaïde Labille-Guiard (April 11, 1749-April 24, 1803) was a French painter who was a master at miniatures, pastels, and portraiture.
Biography on Wikipedia: https://en.wikipedia.org/wiki/Ad%C3%A9la%C3%AFde_Labille-Guiard

Louise-Elisabeth of France, Duchess of Parma by Adélaïde Labille-Guiard
1788 / Oil on canvas / 107″x63″ / Palace of Versailles, France

Adélaïde Labille-Guiard on Artnet: http://www.artnet.com/artists/ad%C3%A9la%C3%AFde-labille-guiard/

Further reading:
https://nmwa.org/art/artists/adelaide-labille-guiard/
https://www.metmuseum.org/toah/hd/lagui/hd_lagui.htm
https://harvardmagazine.com/2009/09/adelaide-labille-guiard