It was the second time I stayed there and it is certainly not the last (unless the flat goes off AirBnB).
Very welcoming. The flat is beautifully decorated and feels very homely.
It is indeed very quiet and although it is right at the centre of the city, you will not hear a single noise. It's ideal for sleeping. It is also great if you need to work quietly on your laptop.
The flat is located next to Rue Montorgueil and all the restaurants and nice bars. Ideal to go anywhere in Paris.