#31176 Henri Julien Felix Rousseau (1844-1910)

The picture has something of this: people, festival, group, wear, man, many, group together, ceremony, performance, costume, celebration, daylight, outfit, woman, dancing, music, crowd, parade.
Perhaps it’s a painting of a group of people standing next to each other in front of a boat with a lot of flags on top of it and buildings in the background.