Do it. I ride in NYC often enough to know how to handle 'combat traffic' situations. That said, Paris was a breeze. As long as you're not too upset by the rental selection (only scooters), you'll find it's the most fun way to get around. 1-2 hours trips may not be as fun, mostly due to smaller wheels and twitchier steering than what you're probably used to on a motorcycle.
The first time, I rented a Vespa GT 150 (maybe 200). Even rode with my wife on the back all the way to Versaille. In Paris, it's EXPECTED that you lane split when possible and that you pull up to the front at every red light. Park on any corner or sidewalk you like.
Second time I could only get a 150 Piaggio. Not as peppy of a scooter, but it got us around. Both times, the going rate was about $175 USD to rent from Friday afternoon until Monday morning. I rented from FREESCOOT (not actually 'free', unfortunately) at the 63 quai de la Tournelle location. You are also MUCH more likely to find someone speaking english in Paris than in other cities.
http://www.scooter-rental-paris.com/
