I went to the opera house (Palais Garnier) on the final day of the trip though I didn't have the plan in that trip when I visited Paris for the first time this year. Because there is the museum in the opera house, we can come in the building even if we can't see a opera.
And,fortunately, we could see the ceiling picture of Chagall at that time. I don't know whether the picture of Chagall is matching with this building or not. However, I was impressed by the glorious picture very much.
To tell the truth, I felt the opera house was better than Palace of Versailles in the splendours of them.