The room is big but there are problems. The bed is a very hard futon mattress on a tatami mat on the floor. The bathroom is in the hallway up 1 flight of stairs & shared with another room. The bathroom door doesn't fit in its frame to latch shut & is secured only by a security chain so it could be opened almost 5 cm gap (which would look straight into the glass shower!). No air conditioning & no fans. Very loud squeaking floor in the hallway/staircases.
Check in was fine, communication was fine. The location prior to booking looked like Sablon near the Palais de Justice but it was actually farther out in Saint Gilles, a 9 minutes walk south of Hôtel des Monnaies metro stationor 9 minutes east of Parvis Saint-Gilles station.
Overall this looked like a good deal but I wish I had looked at hotel prices first, they were actually just as cheap for the same night booking last minute.