There are lots of great museums throughout Paris. If you have a student of art/art history pass you can get into all the national museums for free. In addition, these national museums are free all day the first Sunday of every month, but be warned, they tend to be very crowded on those days, so get there early! For other museums, you can use your French Student I.D. card to either get a reduced-price ticket (tarif reduit), or skip the lines.