Our family of five stayed here and it really was very centrally located - only 15 minutes walk from Notre Dame - but just as easy to get to by Metro if you prefer.
There are several places for a family to eat within a very short distance (three or four within 100 metres) and also plenty of shops and excellent cake shops also nearby. Great value and an excellent location for a visit to Paris - I would recommend it. The apartment itself is as you see it in the photos - pretty bare - but what you would expect and we only ever used it to come back to to sleep in the evening -