I can't recommend Koro and her apartment highly enough.
The apartment itself is just as shown in the listing. Perfect for my wife and 2 boys. The boys had their own rooms, toilet and world on a level below the kitchen/dining-living/main bedroom. Everything was spotlessly clean and there were many tasteful touches of art.
The amazing aspect of this apartment is it location. 1 minute from "Le Marche Des Enfants Rouges" with all its little restaurants and stalls and equally close to the shops of Rue de Bretagne, where you have patisseries, delis, 2 supermarkets, fresh fruit etc etc.. And of course all of the Marais on your doorstep.
Koro herself was the perfect host. Charming, warm and conscientious. Our flight was delayed a couple of hours, but she was at the apartment to greet us at midnight and show us around. She was equally flexible when we checked out the last day. Big thanks to her. Our family is really looking forward to returning to Paris and staying in this apartment again in the near future... Recommended!