The apartment was precisely as described and as per the positive reviews.
Antoine was there to greet us with a bottle of wine, despite a delay in our arrival.
The location was ideal and the view of Notre Dame and beyond was superb.
We walked a lot and mainly used the Pont Marie metro - the train to CDG airport was nearby and easy to access too.
Being on the fourth floor without an elevator wasn't an issue for us even after a long day of sightseeing (and apertif'ing) but do take it into account.
There were some parties along the bank of the Seine til 4am one night but with the front window closed and the bedroom door shut, we had no problems sleeping. We would stay here again in a heartbeat!