Day 2: Spend a Morning at the Museums
Since you don't have that much time, it's a good idea to move quickly in the Louvre, focusing on the big three: the "Mona Lisa," "Winged Victory," and the "Venus de Milo." Once you're done, Café Marly is a convenient and chic spot to grab a bite. The price reflects it, but the view of the Louvre's glass pyramid makes it worth it.
If you have time, head to the lovely Musée D'Orsay. The former train station holds an extensive collection of impressionist and postimpressionist art, with iconic pieces from Cézanne, Monet, and more.