We are a family of 5, 2 adults and 3 boys aged 9-14, we stayed here for 8 days. Overall, our experience was very good.

Pros:
1. Location - this is probably the best area to be in, in Paris. Everything is convenient - groceries, supermarkets, metro/bus access, cafes, restaurants, many attractions, etc.
2. Very quiet - away from the street, looks onto an inner courtyard.
3. Good light.
4. Good heating.
5. Great security - double locked doors at entrance, good locks on apartment door too, all windows open onto inner courtyards.
6. Caretaker is easy to contact. We were initially given the wrong number, but once he met us and corrected this, it was easy afterwards.
7. The kitchen is very well equipped with modern appliances.

Cons:
1. This apartment is really geared more towards 2-4 people staying there, and the amount of furniture, type etc. is geared towards that. We could make it work with 5, but it stretches the water heater, the clothes washing/drying capacity, etc. quite a bit.
2. The overall cleanliness can be improved - there were a few stains on sofa cushions, and the bed covers were dirty. Not a big deal, but since we were paying quite a bit, we expected better.
3. Minor nit: response time for minor complaints is 2-3 days (replacing bad bulbs). This may not be a statement specific to this apartment, however.