Marion has been a great host. I cannot recommend her enough.
Instructions were very clear, she has been very responsive, and check-in and check-out have been super smooth.
The apartment, though quite small, is definitely worth the price. I have stayed at her place for two months, and I had no problem whatsoever.
The only thing that could use some improvement is the wifi. If you need it for work, don't count on it since it has quite a weak signal (the router is in the shared entrance with the other apartment).
Aside from this, I have really appreciated everything else. In addition, a washing machine/drier had just been installed, so a very useful addition for long stays. The neighbourhood is very lively, in the middle of the city center. 15 minutes walk from Centre the Pompidou. The nearest metro station is 2 minutes from the apartment, from it you can get to Chatelet in a few stops, hence everywhere else in Paris very easily. Plenty of restaurants and cafès.