This is a charming and beautifully-located apartment. If you're planning to spend a lot of time in the Marais or near the Place de la Bastille - for example, going to the Opera Bastille - it's pretty much perfect. It's near multiple Metro lines, tourist attractions, the Sunday & Thursday market on Blvd. Richard Lenoir, Pere Lachaise cemetery, the Canal St. Martin and more.
The kitchen is well equipped; there are lots of restaurants and cafes near by, and the excellent bakery/pastry shop at the corner of Blvd. Beaumarchais. It is very quiet and warm (important since I was there in February), well-maintained.
The hosts are lovely, responsive, and accommodating!
I will mention that if you have any mobility limitations, this apartment is not for you. It is up a fairly worn and narrow flight of stairs. I am able-bodied without limitations, and I was very very careful on the stairs, especially carrying my suitcase in and out.