We stayed in Simon's apartment for 5 nights and it was perfect. Our experience was consistent with many of the other positive reviews posted here. Simon was very responsive via text messages, and Gorette was very helpful in welcoming us when we arrived. What we really liked about the apartment was the following:
1) Location !! The apartment is very close to a metro station, so it was very convenient for us to explore the various sites of Paris either by walk or by taking the metro station close to the apartment. In less than 15-20 minutes, we were invariably at the preferred destination for the day. In addition, the neighborhood itself is very safe, so we did not have any issues walking back late at night.
2) The apartment was just the right size for us traveling with our 5 year old daughter. It was spacious, and we were able to make breakfast every morning in the kitchen. The apartment came with a washer/dryer, that allowed us to run a round of laundry before we left for our next destination. Overall it was not too small... not too big... just the right size.
overall, definitely a strong endorsement for anyone looking to spend a few days in Paris with a young family.