We stayed at Catherina studio for 4 days and we had awesome vacation.
Fist the location to my opinion couldn't be better right in the center of the main attractions and night life. (we used the metro once in four days !!)

The studio was very clean and organized, the stairs to the studio wasn't that bad.

Catherina is great person, she was very flexible with the check-in and check-out hours...

To summeriest, this is perfect place for one\couple to stay in Paris.