The location in Montmartre was really good; bars, restaurants, grocery stores and a metro station just a stone's throw away.
The apartment itself was surprisingly spacious with very simple interior, nothing extra but everything we could've needed, from cooking supplies to tv etc. The beds were comfortable to sleep in with big blankets and pillows. As it's located on the 7th floor, we were provided a great view over the area and the Sacre-Coeur from the bedroom and livingroom windows!
The only thing that might cause any problems would be climbing the stairs with heavier luggage, as the building has no elevator.
Overall, I would stay again!