Philippe Jost, a veteran French civil servant and the president of the cathedral restoration effort, and Philippe Villeneuve, the project's chief architect, are seated for the ceremony.

Jost said world leaders who visit Paris often asked to visit the restoration worksite. He said Prince Charles dropped by, for example.

Former French President Nicolas Sarkozy and his wife, the singer and fashion model Carla Bruni, have arrived at the cathedral for the ceremony.

Louis Manaranche said he and his 7-year-old son, Paul, were determined to brave the cold and rain today to watch the reopening ceremony unfold.

"We are Parisians and Catholics and we were very near from here when the cathedral burned five years ago,” said Manaranche, 38, a teacher and headmaster at the nearby Catholic school Collège Stanislas Paris.

“We felt that we were living a tragedy,” he said.

Manaranche said he had secured three places for himself and his two eldest sons at an upcoming mass at the cathedral on Tuesday.

“We are very excited,” he said, as he expressed gratitude to the hundreds of people involved in the cathedral’s restoration. “We are very very grateful.”

A number of people watching the reopening ceremony outside the Notre Dame could be heard cheering as Macron appeared on the screens set up outside the cathedral.

The crowd has swelled to thousands of people lining the streets, many bundled up in winter coats and holding umbrellas.

Due to poor weather causing delays, Prince William’s meeting with first lady Jill Biden at the U.K. resident has been cancelled. Instead, he will meet her at the Notre Dame ceremony.

Here's an interactive look at the parts of the cathedral that were destroyed in the mammoth blaze. Scroll through the page to get a closer look.

The French president and his wife, Brigitte, have arrived at the cathedral.

American carpenter Hank Silver is one of the lucky invited guests inside Notre Dame tonight. He helped rebuild the nave wooden framework of the rooftop.

Silver said there is a lot of excitement in the air. The people around him are “thrilled and emotional” to be part of this opening celebration, he added.

Elon Musk is here in Paris tonight. The tech billionaire and close Trump ally did not travel with the president-elect, according to a spokesperson for the presidential transition.