Study for a costume ball given by the Princess of Sagan Eugene-Louis Lami (1800-1890)

The picture has something of this: saint, people, book, god, holy, interior, fresco, Renaissance, church, religious, ancient, man, antique, Apostle.
Perhaps it’s a painting of a group of people standing in front of a red curtain with a man in a suit standing next to a woman in a white dress.