We (a group of five friends) stayed at Valerie's apartment for two nights. Contact with her before arrival was friendly and she responded quickly to all our mails. The apartment is in a beautiful location just next to Notre Dame with very good access to various metro and train lines. There are plenty of restaurants and bakerys (our favourite was Eric Kayser in the Rue Monge) close by as well and most major sights of Paris are in walking distance (if you don't mind walking quite a bit). There is a beautful little market on Saturday on the place just in front of the house with cheese, fish, vegetable and other stalls.
The apartment fully matches the pictures, is nicely decorated and was very clean. For two nights, the space was fine for 5 people, for a longer stay we might have felt a little cramped (some very tall people might struggle with the toilet which is really quite narrow).
We had a great stay at Valerie's place and I would fully recommend her place and her as host to other travellers.