In the nave of Notre Dame cathedral, huge scaffolding supports a working floor, some thirty-three metres high. It is in this space that craftsmen bustle about supporting the sexpartite vaults of the building, each resting on six pillars.
This “timbering” of the parts damaged in the April 15, 2019 fire was launched in March 2021: several half-hangers, strictly conforming to the shape of the vaults, and each weighing more than 1.6 tons, have already been installed.
https://fsspx.news/en/news-events/news/notre-dame-de-paris-timbering-vaults-progressing-67693