Anton von Maron – Maria-Theresa of Habsburg (1717-1780), Empress of Austria, Queen of Hungary (1740) and Bohemia (1743), wearing widow’s dress, presenting the crowns of Bohemia and Hungary and the Imperial Crown Château de Versailles

The picture has something of this: people, woman, furniture, seat, room, wear, dress, indoors, portrait, sit, veil, two, position, reclining.
Perhaps it’s a painting of a woman in a black dress sitting at a table in front of a mirror with a cane in her hand.