Constantin's apartment is a great place to stay! It's spacious, fully equipped, and very conveniently located. Three different metro lines are an easy walk and Sacré-Coeur is a short (10 minute), uphill stroll. The neighborhood is lively and not very touristy. Lots of cafés, take-out food options, and everything else you might need (bakery, cheese shop, wine store, grocery store, pharmacy). I'm a light sleeper and despite the street life, the bedroom is quiet, situated on a courtyard in the back. The unit is three flights up from the street which was fine for me but might be a consideration for some. The only problem I had was at check-in, and that wasn't Constantin's fault. The previous guest didn't leave the key at the proper location and Constantin, despite being out of town on business, did everything he could to smooth the wrinkles and accommodate my request for an early check in. I stayed for 2 weeks and hope I can come back again!