ca. 1782 Madame Antoine Seguier, nee Vastal by Pierre Adolphe Hall after Alexandre Kucharski (private collection)
A good biographical article about the sitter can be found with this image here.
From www.pastellists.com.
This is an excellent depiction of a fichu and the late 1770s-early 1780s tall coiffures that were wider at their summits than at their bases, a mild example of a coiffure à la quinot.
Keywords: 1782, Hall - Pierre, French, long high straight coiffure, jeweled feathered cap, vee neckline, fichu, scoop décolletage, ruffles, bows, close sleeves, tent bodice