I would suggest finding another hotel. While the Regina Opera is located in a central location, the area was rather uncomfortable. The road that it was located on was a gathering spot for what seemed like homeless persons with no place to urinate but the street.
The hotel itself was mostly clean and looked very nice on arrival. However the room barely fit the bed and the lift was very sketchy. oh right and there was a dead bird hanging from a screen canopy over the center courtyard, right outside our window. Overall we still had a lot of fun in paris, and rarely visited the hotel.