I stayed at Montmartre for 3 months for work and it was great. You will find everything you need in the (very clean) apartment and more (cooking utensils, bed sheets, towels, washing machine, dryer, hair dryer, etc.). It is small, but perfectly ok for one person and even for two for a short amount of time. The bed is big enough for two as well.
Igor and Pavel are really nice and helped/responded on very short notice.
The location is, no need to say, awesome :) The flat is super close to Sacré Coeur and all the other touristy things in Montmartre, but also close (2 minutes) to the métro line 12 and about 15 minutes to métro line 4. There are a lot of great restaurants in the area, too, supermarkets, boulangerie, post offices, etc. You can also walk about 30 minutes to Gare du Nord or Gare de l'Est which I found personally very convenient.
In the summer time the area might be a bit louder (because of the tourists and taxis going up and down to the church), but the window closes pretty tightly. The room is not warm, which was a relief during the 2022 heat waves, but you might need some warm socks in winter ;)
All together, I definitely would recommend this flat and I wished that all AirBnBs were maintained like this one.