Orsay is an old train station converted to a museum that hosts mostly Impressionist paintings. I really like this better than the Louvre.
Sisley,Monet, Manet,Degas, Pissaro and Van Gogh are all here as well as a number of these artists' sculptures.
They also have a very good cafe. The Cafe serves quiche and pizza and sandwiches.
Museum is closed Mondays.