Pastel on paper laid down on canvas
Adélaïde Labille-Guiard (11 April 1749 – 24 April 1803), also known as Adélaïde Labille-Guiard des Vertus, was a French miniaturist and portrait painter. She was an advocate for women to receive the same opportunities as men to become great painters. Labille-Guiard was one of the first women to become a member of the Royal Academy, and was the first female artist to receive permission to set up a studio for her students at the Louvre.
https://en.wikipedia.org/wiki/Ad%C3%A9la%C3%AFde_Labille-Guiard
Lovely look they share, explains a lot with just that.