We just got back from spending 2 weeks in France. Our first 4 days were spent at Jacques studio apartment and it was great. Jean-Paul was waiting for us when we arrived (and we were a little late). He explained how everything worked. He was very friendly.
The apartment is in a great location in the middle of Marais. The Metro and grocery store are quite close.
The only small negative is that, even though the pictures of the unit are fairly accurate, they do not fully convey how small the unit is. It is tiny! For my wife and I it was fine but if I had more people with me I would need to rent a larger unit. The stairs to the loft bed are quite steep and there is very little head-room over the bed.
There is a washing machine in the unit but no clothes dryer (hang dry in tub)
Overall, very pleased.