We had a lovely week in Le Marais, Iris' apartment is so central to everything and you'll be a part of the local scene. In other words - not surrounded by a million tourists. So many restaurants, bars, cafes, grocery shops, specialty food stores, easy public transit (really really convenient). You will be spoiled for choice and will feel like a local.
Be aware that this is a very busy area and can be loud. Not a fault of her apartment, it's the price we pay for such easy convenience to the best of everything nearby. Also, the bed is barely (?) a queen size. Just a heads up if this is important to you from a comfort perspective. But the apartment is very unique and you will be guaranteed a memorable experience. Paris at it's best. Thank you, Iris!