Guillaume II Coustou (1716-1777) Francois-Hubert Drouais (1727-1775)

The picture has something of this: people, woman, wear, portrait, facial expression, man, girl, seat, music, two, veil, dress, furniture, indoors, model.
Perhaps it’s a painting of a man sitting in a chair with his hand on his knee and his right hand resting on the arm of another man’s arm.