We stayed for 2 nights at Natacha's flat and it was a great experience. Bercy area is great, close to everything and quiet the weekend! There is a lot of restaurant or snack there.
Gare de Lyon is 10mn walking and bercy station 5mn.
The rooms is normal size with a good bed and balcony. The breakfast is very good!! (orange juice, fresh Baguette, jam or french cheese...) good to start a big day of visit!
Natacha and Thierry are friendly, we have a good discussion about everything...
I recommend this room if you are looking for a sharing experience not only a place to stay! we have really appreciated our stay there!