Mat is a kind, considerate and attentive host. He addressed a stopped drain for us immediately, had advice for local travel, and even emailed an news article addressing our specific interest. Great person.
Mat's place is subterranean, and to access it, you descend a spiral staircase to the flat. In a reflection of consideration, multiple natural light portals exist to make the flat feel less underground. One benefit of the flat's location is that on hot days it stays cool, and on cool days stays warm.
The flat has everything you need to be comfortable in between running around Paris: small kitchen and fridge, including wine glasses, glasses, dishes, pots, silverware, etc. The large couch becomes a full-size bed, a second bed is in the bedroom, which is separated and private from the main room.
Bathroom includes a shower with two heads (i loved the rain shower, and there's also a separate hand spigot head). Also included is a washer / dryer for extended stays.
Overall we really enjoyed the location, the amenities and the price of Mat's place, and having a great host makes renting even better.