Firefighters have managed to save and preserve the main structure of Notre Dame, according to a fire official who told AFP.
Another official has added to Reuters that the two main towers have also been preserved.
According to the Guardian, a preliminary investigation has revealed the fire started accidentally.
One firefighter has been injured while tackling the massive blaze at the 850-year-old cathedral.
A police drone image has revealed the true extent of the devastating blaze that has shocked many around the world.
Thankfully, all precious artefacts and artwork have been saved from the historic building, according to a Notre Dame cathedral priest.
In a tweet, French journalist Nicolas Delesalle cited Père Frédéric, writing: "Good news: all the works of art were saved. The treasure of the Cathedral is intact, the Crown of thorns, the Holy sacraments."
The historic building's spire and roof have already collapsed. No casualties have been reported as of yet.
The cause of the fire is not yet known, however, officials have indicated it could be linked to current renovation work.
The French President, Emmanuel Macron, has cancelled a planned public address and has arrived at the scene.
Last year the Catholic Church launched an urgent appeal for funds to repair the building, which was showing serious signs of decay.
The construction of Notre Dame - which means 'Our Lady' - began in 1160 and was mostly completed a hundred years later in 1260. It has been modified on numerous occasions throughout the centuries since.
On Twitter, the mayor of Paris, Anne Hidalgo, described the fire as 'terrible'.
She said: "A terrible fire is underway at Notre-Dame Cathedral in Paris. The @PompiersParis are trying to control the flames. We are mobilised on the spot in close connection with the @dioceseParis. I ask everyone to respect the security perimeter."
More to come.