French President Emmanuel Macron on Thursday observed the work to salvage and restore Notre-Dame de Paris, two years to the day after flames ripped through the cathedral’s centuries-old attic and sent its spire crashing through the vaults below.

In the hours after the blaze, Macron promised a distraught French nation that the cathedral, which dates back to the 12th century, would be rebuilt and later said it would be reopened in some form to worshippers by 2024.

More than 700 days after workers scrambled to shore-up Notre-Dame’s flying buttresses, stabilise the bell towers and install hundreds of movement sensors, the effort to make the site secure ahead of restoration is almost complete.

From the rooftop, now largely covered by a complex scaffolding structure, work platforms and in places a tarpaulin “umbrella”, Macron peered down into the cathedral’s damaged transept and thanked workers on the site.

“We’re all impressed with what we see, with the work that has been achieved in two years,” Macron told a group of workers with the Paris skyline behind him. “Bravo and thank you.”

“We’re arriving at a critical juncture,” General Jean-Louis Georgelin, the former army chief of staff named by Macron to head the renovation, told France Inter radio. Restoration work would begin before the end of 2021, he said.

The first phase of the project was complicated by the need to remove 200 tonnes of twisted metal after the fire consumed 40,000 pieces of scaffolding that had been erected around the spire at the time of the blaze.