Myself & boyf went to Paris for NY a couple of yrs ago, had fab time... def recommend. We went for a fab (but v. expensive) meal nr Montmarte early on in evening and went up to the Sacre Coeur for Midnight. Lots of locals there and a good view over the rest of Paris and the fireworks. As for the rest of the time I would suggest wrapping up warm and wandering around the sights, romantic. We stayed in an area not too far from the Montmarte, underground transport system good so wherever you stay isn't a problem. Good to bear in mind where you'll spend new year incase you have to walk back to hotel in the early hours though! Have a great time!!