We spent a great holidays in the apartment as the location is fantastic. You can go everywhere on paris thanks to the subway in republic where you have most of the lines. The 2 queen beds are very comfy as well.
We (a couple) were with our 2 kids (3 and 4) and my mother. There is a great park one block away that the kids loved.
There are toys as well in the apartment that were very appreciated.
The apartment is old and need a bit of a refreshment but it was ok for us as we spent most of our days outside.
For Americans it will be definitely too small as it is a typical old Parisian apartment with only 1 bath.
All in all we spent great holidays.