This is a nice place to stay, and VERY accessible to Montmarte. It's a bit smaller than it looks in the photos, and the bed is quite firm (as is the couch), but we were still very comfortable. The kitchen is tight, but well-stocked, although who's making dinner when there are so many good options just outside? It's up 3 flights of stairs, but we got used to that pretty quickly. The listing advertises a fireplace, but it appeared to be non-operational, and we didn't ask. The only issues we had was that the jacuzzi tub didn't seem to work (it appeared the breaker for it in the breaker box was taped in the "off" position and we didn't want to mess with it), and the shower is hand-held only - there's no place to mount it to have two hands free while standing.
There was some confusion about how long it would take before someone was there to check us in, but it appears there is a property manager on-site, so that actually went very smoothly.
We would definitely recommend for couples who want to explore the northern side of Paris. More than 2 people would feel very tight.