Nicolas' apartment is lovely, quiet, stylish and has all the amenities you will need. My husband and I, along with our toddler stayed there for three nights and we were very comfortable. The location was great as Le Marais is an ideal spot from which to explore the big sites of Paris. Additionally, Nicolas is an extremely nice host and made sure we settled in well. He also responded to every message very quickly so I always felt we had help if needed. I highly recommend his place for an individual or a couple!
The only draw back for us (which was totally our fault) was that when putting our kid to bed at 8pm we had to hang a sheet on the french doors to block the living room light. That's the only thing I wish we'd thought about when looking for a place with bedroom doors.