Gustav IV Adolf (1778-1837), King of Sweden Lorens Pasch the Younger (1733-1805)

The picture has something of this: people, woman, seat, wear, room, furniture, child, dress, portrait, girl, indoors, performance, two, sit.
Perhaps it’s a painting of a young girl holding a musical instrument in front of a man in a blue and white outfit and a woman in a white dress.