As a young person, I was member of a professional choir that would tour, do residencies at EU cathedrals, and, on one occasion, sang here. We were surprised to find that the acoustics were actually quite bad for such a vaunted place! These many years later, it was interesting to learn that we were not imagining things, and that the acoustics of the space were factored into the recent restoration: https://www.nytimes.com/interactive/2023/03/03/magazine/notre-dame-cathedral-acoustics-sound.html All that to say, it must have been special indeed. To hear one of the greatest living musicians perform in a place that sounds better than it has in centuries. Whew!