Isabelle's place is very cozy and has everything we needed for our family trip to Paris. We were 3 and had no problem at the apartment. It is near to public transportation: just a short walk to Republique and there is also the bus line 75 that you can take from Ile de la Cite which passes right in the corner of the apartment.
We didn't meet Isabelle, but Evelyn, who received us in the check in, was really nice and helped us whenever we needed during our stay.
We definitely recommend Isabelle's place, but bear in mind that the apartment is located in the 4th floor without lift, that may be uncomfortable for elderly or people with restricted mobility.