I very much enjoyed my stay of several days/nights at Jad's place.
It's very well situated: you're close to the useful metro line 7 (stations: les Gobelins, Censier Daubenton); you're also about 15 minutes' walk from the Port-Royal RER station, which is a brief train ride from the Gare du Nord; and on foot you can quickly get to various nice spots in the 5th arrondissement, including plentiful bars, cafés and restaurants (a little discovery for me was the Square St-Médard and the rue Mouffetard, very close by).
The terrace is one of the big pull factors of the apartment itself, but everything else in the property is also fine/good. For me personally it was a big plus that you can actually sit comfortably and healthily (from the point of view of one's back) on the sofa bed when it's folded up, and in the small chair: a comfortable seat is not guaranteed in every AirBnB property, in my experience, especially in big cities. The sound insulation in the block lets through a bit of normal domestic noise from the neighbouring apartments, but this would be the same in many other Parisian blocks (and some hotels) and it wasn't a problem, as there was no anti-social behaviour. On the other hand, you're very well protected from traffic noise - certainly in the apartment, and even to some extent on the terrace, as this is looks out onto a large internal courtyard.
Finally, Jad was a friendly and communicative host.