This is a stay with "wow" factor for how cool it is! We found it very convenient to all the artsy neighborhood spots, very close to the river walk, awesome restaurants and bars, and shopping. The flea market at St Michel Basillica is not to be missed by any vintage-phile! We felt quite safe even though the apartment is on a quieter back street.
I've seen other reviews speak of the stairs. It's 10, then a landing then 10, its not exactly Mount Everest and we found them completely doable. The apartment is easy in and out with the locks, etc. Everything was in working order and spacious and a fully stocked kitchen. There's easy tv and Netflix for you english speakers.
The space IS an old wine tunnel I believe and so inherent in this is a bit of stone dust and a humid, cool environment. I don't know that humans are meant to LIVE in this so two nights were perfect again for the WOW coolness factor but I would hesitate to book longer then a week. However, if this space is available BOOK IT NOW! Because its pretty amazing.