We stayed 3 weeks at Marie’s apartment: Very nice spacious apartment, in the middle of the Marais!, 10 minutes to the Métro, nicely furnished, everything was provided! (e. g. shampoo, shower gel toilet paper, coffee + tea, oil, salt+ vinegar, dishwasher tabs, washing liquid etc.), definitely non-smoking, clean, lots of space to put your own stuff (however Marie lives in the apartment, so her things are also there, but the apartment looked charming to us and not cluttered), the bed is a normal French bed (1.40 m width, 1.90 m length) and rather hard. You can easily stay there with 4 people (our 2 daughters visited us), but for sleeping in the living room you should not be taller than 1.75 m.
We enjoyed our stay very much!