We family of four stayed in this apartment for nine days and really enjoyed our stay. The apartment location is very convenient, in a good neighborhood, about 15-20 minutes walk to Louvre, the Hôtel de Ville or to the Ile de la Cité. Arts& metier Metro station is across the street from the apartment, and there is another one, Réamur-Sébastopol, ~7 minutes walk away, if there is a need to use metro. The apartment has everything that is necessary with fully equipped kitchen. Bakeries and few groceries are close by as well.
Chloe also provided us with the information about surrounding area.
Just a bit of warning: the apartment is on the 4th floor with narrow spiral stairs to the 4th floor and there is no lift, so it may be difficult to climb for small children. Except this bit, the flat is a very good place to stay. We highly recommend it.