Notre Dame's famed 8,000-pipe organ, known as the voice and soul of the beloved cathedral, will be "revived" after a five-year absence in one of the highlights of this weekend's reopening ceremony at the landmark.

The vast organ escaped the worst of a devastating 2019 blaze that destroyed Notre Dame's roof and spire, but it suffered minor water damage and was left covered with ash and a film of poisonous lead dust.

Workers had to dismantle it to clean its five keyboards, winch down the pipes -- some of them are almost 10 metres (32 feet) long -- and replace internal leather components.

The entire ensemble was re-tuned at night over a six-month period ahead of the reopening ceremony on Saturday that will be attended by incoming US president Donald Trump, among other VIPs.

After symbolically knocking on the door and then entering the cathedral at the start of proceedings, Paris archbishop Laurent Ulrich will call on the instrument on eight occasions, commanding it to "wake up".

Organist Thierry Escaich and three colleagues will be at the keyboards and stops, responding with bursts of improvised playing that will once again reverberate throughout the cleaned Gothic vaults of the 12th-century edifice.

"Reviving the organ is done at almost every inauguration of an organ that has been damaged or is new," he told AFP. "It's a ritual within the rituals of the church because it's often said that the organ is the soul of the church."

The ceremony is about "giving it new life and reintegrating it into this new cathedral with its freshness".

The Notre Dame organ can be traced back to 1733 but has undergone multiple modernisations and enlargements since then.

- 'Magnificent' -

For aficionados, the organ is likely to sound slightly different given that centuries of dust have been scraped off the limestone walls of Notre Dame which are now fully exposed and cream-coloured.

"For the last month I've been able to come back to work with my colleagues, to try all the instruments," Escaich said, explaining that different keys of the organ correspond to the instruments of an orchestra.

He plans to use those representing the trumpets of the apocalypse -- a biblical story in the Book of Revelations -- during one of his improvisations.

"The sound has remained magnificent," he said.

Notre Dame's organ is the largest in France, but not the biggest in the world.

That title belongs to an instrument in Atlantic City in the United States which has around 33,000 pipes and underwent its own restoration in recent years.

Saturday's reopening ceremony for VIPs and foreign dignitaries will be followed by two religious services on Sunday.

The cathedral, a symbol of Paris and one of the best-known landmarks worldwide, has been restored at a cost of 700 million euros ($750 million) from public donations.

AFP

The immense organ has been likened to the 'soul' of Notre Dame © STEPHANE DE SAKUTIN / POOL/AFP

Not a pipe dream: Notre Dame's organ to be 'revived'