This was auctioned by Sotheby’s as Portrait of a Lady in an Elaborately Embroidered Blue Dress so this may not be the infamous Maria Luisa at all.
From triinochka.ru/post396110573/.
Maria Luisa’s dress has a shovel waistline like a robe à la française, but no (visible) sacque in back. Her stomacher and over-skirt are trimmed with sheer material. All parts of this dress use the same material.
Keywords: 1765, Baldrighi, María Luisa de Parma, Maria Luisa di Borbone-Parma, Luisa Maria Teresa Ana, princesa de Austurias, reina de España, Bourbon family, Borbone family, Borbón family, Princess, Queen, wavy coiffure, hair jewelry, bandeau, earrings, fitted bodice, U-neckline, stomacher, floral robings, elbow length tight sleeves, bows, floral sleeve ornaments, lace engageantes, shovel waistline, over-bodice, flounces, under-bodice, panniers, fan