Respiration

Instead of reconstructing the spire and roof of Notra Dame as it was, I would reconstruct it as it was just shortly before the fire took at it down. Naturally it would be built of reinforced metal, but it would exactly resemble the twisted and charred pointed spire and roof.

Once a year a series of gas fed fires would ignite and when supplemented with the right particles, the flames would roar into the night in a reanactment of the terrible conflagration. This would be a unique spectacle of celebration and remembrance.

With extra funding, a mechanical Quasimodo figure might be seen fleetingly, moving around frantically just before the flames envelop the entire structure.