It was a really nice characterful flat, in a fantastic location. The Isle St Louis is very attractive, and there are plenty of food shops and restaurants near the flat. Nadia, who met us on arrival was lovely, very welcoming and helpful. The wine and chocolate awaiting us was a kind gesture. Very comfortable beds, the shower worked very well, and the flat was warm -we didn't need to use the heating much at all (despite the weather outside being pretty cold). The flat might be more convenient for 2 people than 3, as you have to move the furniture to unfold the sofa-bed every night, but if you don't mind doing that, it's fine! The pillows for the sofa bed are hidden inside it, it took us a while to find them, but they are there! There doesn't seem to be a way of recycling, but I assume that is a failing of the local government, not of the owners! Best way to arrive is by RER, if you are coming from Gare du Nord (or Charles de Gaulle airport), to St Michel/Notre Dame. I recommend bringing scissors if you think you may need them (that's the only thing we felt to be lacking)
All in all, we really enjoyed our stay.