This is an absolutely beautiful little room in Montmartre, decorated in exquisite style. We loved the balcony - there was enough room to sit and read a book, eat breakfast, or have a drink in the evening (with a nice view!). There is a lovely restaurant up the road (Hotel Rochechouart), a grocery shop (Carrefour) and nearby transport links so it is in a good location.
The bathroom has a lovely shower and is beautifully designed, but the toilet is not in the actual room itself. However, it's just opposite the front door so this isn't really an issue - you'll just need to take a key with you. It is a slight downside to not have a lift up to the room, but understandable and justified as elevators are so rare in Paris. The steep climb was worth it for the view (even with a suitcase!).
There's no aircon, but the curtains are very thick and (I think) black-out, so if you shut them during the day the room doesn't get too hot at all. It was mid-30 degrees when we stayed, and we were absolutely fine in the apartment. There was also a fan which worked fairly well.
Apartment was clean and stocked with the essentials - tea, coffee, shower gel, shampoo. Raphael's check-in/out instructions were clear and his recommendations in the local area were great. We also tried Boulangerie Leonie and we loved it!