Parisians are breathing a sigh of relief to see Notre-Dame Cathedral still standing.

The 850-year-old Gothic church has been severely damaged by fire.

Windows have broken, artworks are damaged, the roof has collapsed and the church's iconic church spire has been destroyed.

But French Heritage Society deputy director Karen Archer told Mike Yardley things could have been worse.

"To think Note Dame could actually disappear is inconceivable. So it's very reassuring to see that although the roof may be charred, it's still standing."

Archer says it's difficult to put a timeframe on when the building will be restored as nobody has been able to access inside the building.

"They first have to stabilise the building, then they can assess what the damage has been and start looking at what they need to do to restore the building."

Restoration work on Notre Dame, which began in July 2018, was set to be carried out in several phases over 20 years.

French president Emmanuel Macron says he wants to see the fire-ravaged Notre Dame cathedral rebuilt within five years.