The Musee d'Art Moderne de Paris (MaM) is a great museum to visit and the general entry is free !! My husband and I enjoyed walking around the different exhibits and really enjoyed our time.
A note though is they are closed on Mondays.
The museum's permanent collections, with more than 15,000 works of art, show the diverse art trends of the 20th century: cubism, Ecole de Paris, abstract art, new realism, etc. The museum houses works by Pablo Picasso, Juan Gris, Henri Matisse, Alberto Giacometti, Georges Braque and Yves Klein. In parallel to these permanent collections, large temporary exhibitions are organized. A cafeteria and bookshop are some of the additional services offered by the museum.
Great place to come while in Paris. Budget friendly activity to do all year round.