The apartment is centrally located and steps away from the metro. The photos are very accurate - it's a small apartment with the necessities. The building is very quiet even though it's on a busy street.
The bed was comfortable and it was great to have a little nursery area for our 18 month old. The nursery nook is separated from the main living space by a heavy curtain (so not sound proof). It included a changing table, crib, and black out curtains. We brought a white noise machine and our baby slept very well.
It was very hot during our visit to Paris (90+ degrees F) but the apartment stayed comfortably cool even without AC.
As Camille mentions, there are four flights of stairs which are very narrow. It was a little tricky getting our luggage and baby up the stairs when we arrived/departed but not a problem during our stay as we have a small, lightweight stroller.
We would recommend Camille's apartment, especially if you are traveling with a baby.