The four of us (2 adults, 2 kids) stayed in the apartment during 2 weeks in December 2013. It was perfectly sized for our little family and each day, the morning bathing sun filled us with joy for the day :-)
Positives for us:
-Celine and Remi were great.
-No TV in the living room (yes, a positive for the kids :-).
-The apartment orientation providing sun in the morning in all the rooms. Hence the radiant luminosity.
-The balcony to enjoy coffee while the sun is rising.
-The children bedroom perfect for our 2 kids, especially with all the books and toys already there.
-The excellent and fast wifi connection.
-The Parc des Buttes Chaumont just across the street.
-The shops in the streets nearby.
Negatives for us (at the time of the rent):
-The master bedroom's bed was too narrow for us 2 (adults).
-There was a heating problem so the apartment was rather cold during our whole stay, especially at night, so that we had to wear more clothes (including the children) when sleeping.
-The bathroom faucet was only delivering freezing water and had not been fixed before our arrival, and nothing was arranged later to fix it either. Not pleasant when we wanted to brush the kids teeth or simply wash their hands.
-The bathtub faucet was not delivering enough hot water for us 4, so that we had to shorten our respective shower time. We got caught the first day and I found myself covered with shampoo and soap just as the hot water supply ran off.
Still the overall experience was great and we enjoyed a lot our stay in Paris :-)