I stayed at Isabelle's place for one month. It is very well located no more than 5 min walk to Montparnasse and 2 other metro stations even closer. The flat is beautifully decorated and spacious as far as studios go in Paris. The bed is very comfortable and a major plus.
Isabelle herself is a great host and always gets back to you about any questions you might have, a pleasure to deal with.
I would recommend this place to any of my friends with confidence.