We liked our stay in the appartement. It is very well located with tube stations, shops and restaurants nearby. The neighbourhood is very lively but the apartment is quiet. Very easy to walk trough paris from this central location. The building himself is quite old (especially the stairs and the courtyard) but inside is as described.
The only inconvenient is the bedrooms are quite small (difficult with big luggages) and there is only one ensuite bathroom (we were only 3 so not a problem). The pillows are quite small so could be a bit uncomfortable and the floor is cold (bring you sleepers).
Overall a very good rental and great experience with checkin and check out