We had a nice stay at Serge's place. It has a nice view of the surrounding area and the top of Sacre Coeur. We found the kitchen well-stocked when we wanted to make a charcuterie board from our finds at the market.
The area was a bit more touristy than we expected, so the living room (with pull-out couch) was loud at night. Also there are 6 flights of stairs to get to the apartment, which wasn't a problem for us, but just something to note.