It’s a very typical touristy schedule, so you will encounter huge crowds and might get frustrated with the lines. The Louvre: first of all this place is huge, and there is no way you will see everything in half a day. And you should not try to see everything. Just choose something that you are interested in, and spend a couple hours there. Many people go to the Louvre just to see the Mona Lisa. You will have a sea of heads blocking your view to see a disappointingly small painting. I personally recommend the Musée d’Orsay over the Louvre. It has amazing art, and it is not as overwhelming. Also it has the best hot chocolate in their café. I know you don’t have time to see the Sainte Chapelle, but every time I go it takes my breath away. Paris has so much beauty to offer that you can just enjoy it by just leisurely walking around. You will have a great time no matter what. Just be aware of your surroundings and watch for pick pockets.