My wife and I stayed at the Rive Gauche Hotel and Conference Center in May of this year, as it was the only availability we could get with points in Paris during the time frame we wanted. Initially (before we got there) we were a bit dissapointed as it was in the 14th, and in the past we've stayed at the Mariiott property on the Champs Elysee, which we absolutely love.
Much to our surprise, this property was fantastic (we were expecting the typical 'conference center')!!! We were upgraded to a junior suite, and the Metro was one block away. The service was excellent. We were able to get anywehere in the city within a 20 minute Metro ride, and we found that the 14th is a great place.
There was one person in the Executive Lounge that really impressed us - Liz Averall. She is an American that has been living in Paris for several years and attends (grad school) the American University. It was a pleasure to see her every morning over breakfast and chat. She was able to help us make several of our travel arrangements and was just a great person.
I would highly recommend this property and when there, look up Liz.