Paris at night is absolutely gorgeous. I was usually exhausted by nightfall with all of the exploring I was doing during the day, but I tried to take a walk along the Seine every night before bed.
Tonight I wandered off track a bit to find the street corner from Midnight in Paris... where Owen Wilson's character goes every night at midnight. If you haven't seen the movie, you must. It was very good, and one of the things that made me finally bite the bullet and book this trip for myself.