Check out Rick Steves' book on travelling in France. It gives you many educated suggestions on EVERYTHING to see and do, places to stay, restaurants, etc.
Study the links below and save yourself some time and cash.
https://www.ricksteves.com/europe/france
As for The Louvre and The Orsay - both great museums and pretty close to each other but don't think doing them in one day. Orsay, yeah, Louvre, no.
The impressionist paintings at The Orsay is quiet impressive.
http://www.viator.com/Paris-attracti...-a577?pref=204
The Louvre - well, for my taste, go live there. It would take you maybe two weeks to see just the most important history there. If you're not already aware, you'll be shocked at the size of the Mona Lisa. When walking around, just look up.
To me, it was clear ole Napoleon was one great conqueror but he was also quiet a plunderer and thief of many great treasures.
http://www.viator.com/Paris-attracti...9-a73?pref=204