We recently stayed at Invalide Parisian Flat. There was five of us and you couldn't be more central than this. Most of the major Paris sites are within walking distance. The check-in went smoothly even though Jeremie wasn't there to meet us. It is actually his apartment so you feel that you are staying at a friends house. Decor is great and the bathroom and shower is fantastic. Food market is right next door so you can easily shop and prepare your food in the flat. The extra cot in the living room made it a tight squeeze so I would suggest no more than two couples. We were a family so it was okay. Would definitely stay here again.