It was a hot week in Paris, so we bought a second fan for the apartment. It, like many apartments in the city, has no AC. Also be aware that it is on the 3rd floor up a narrow winding staircase.
On the plus side, Location location location!. It is hard to be more centrally-located, right on the St. Louis island. The whole area is charming and the side-street is quiet and away from the traffic and tourists. Additionally, communication from Leo was clear, the apartment was clean with a serviceable galley kitchen and washer/dryer combo.