The flat is basically one room with small compartments for bathroom (including shower), washing machine and kitchen (=stove+fridge); within maybe 20 square meters you have everything you need even for a longer stay. The bed is wide, comfortable for one person but might be suitable also for a couple that doesn't mind sleeping close to each other. The window is of good quality and blocks the traffic noise of av.d'Italie, which is busy even at night (sleeping with the window open didn't work for me). From the window you have a nice view south (outward from Paris) over the roofs of the neighbouring houses, with higher buildings further away.
The flat is located in the 8th (topmost) floor of a typical old-fashioned Parisian house with wooden staircase and elevator, Parisian flair guaranteed. The house is clean and is taken care of on a daily basis by a young man. It is inhabited by young people (students?) as well as some old ones (as far as I can judge from the few encounters). Immediately beside the house entrance you have an ATM as well as a bakery providing fresh croissants and baguettes. In the next block you find a shopping mall (called Italie 2) spread over several storeys, including a Carrefour (French supermarket). The metro (underground) is in walking distance, either at station "Tolbiac" (line 7) or "place d'Italie" (lines 5,6,7); the metro needs at most 15 minutes to reach the city center.
The hosts, Delphine and Adil, are nice and helpful. They provided food for the first day and responded quickly to questions during the stay (phone or email); they speak (at least) French and English. They live and work nearby, so can easily come by if needed. Checking in and out at a time convenient for me worked perfectly.

Gernot from Austria, who spent two weeks here in September 2013 and might well come again