Highly recommended comfortable & unique accommodation!
I was in Paris for a week-long conference, to which I traveled daily by Metro. My wife enjoyed the neighborhood, and having a "home base" in Montmartre.
We enjoyed our stay, and are grateful to Alexandre for welcoming us, showing us how to work the washing machine, and providing a notebook of helpful local recommendations.
(I cannot comment on the air conditioning because we never needed it. Even on warm days in June, the apartment was very comfortable with the windows open.)