I booked pretty spontaneously and had a great stay, the staff was very friendly and helpful.
The room wasn't huge, but it didn't feel cramped either. On the other hand the bathroom, that you enter through a tiny door was rather spacious and fairly recently renovated.
Depending on the room you can see the Jardin du Luxembourg through the windows. Notre Dame, Louvre, Eiffel Tower, Pont Neuf and other sights and parts of the inner city are easily reachable on foot.
An amazing place to stay while being very reasonably priced. If we come back to Paris, we'll be back here as well.