Montrealers watch in shock as part of Notre-Dame Cathedral decimated by fire

Emergency crews worked for hours to douse a fire that devoured significant portions of Notre-Dame Cathedral in Paris and some Montrealers are looking on in shock.

The pastor of Montreal's Notre-Dame Basilica, Miguel Castellanos, said "words are not enough" to describe what he feels about the fire.

The spire and roof of the cathedral collapsed as flames chewed at the building Monday.

"My prayers are for the French people, the Diocese of Paris, and everyone who will have to work hard to rebuild an international treasure, eternal and powerful," Castellanos said.

Alain Faubert, the auxiliary bishop of the Archdiocese of Montreal, said whenever he goes to Paris he makes a point to stop by the cathedral.

"Notre Dame is not a building, she's an old lady that we come and say 'hello' to and pay homage," he said.

Faubert said that despite being devastated over what was lost, he is hopeful for the future.

"I am certain that God will make something great out of this mess," he said.

Quebec Premier François Legault tweeted his condolences, saying "Notre-Dame Cathedral in Paris is a gem! My thoughts are with Parisians today and the firefighters who fight the flames."

Montreal Mayor Valérie Plante said the building is "part of our collective history — literature, cultural and religious."

The lights at Montreal City Hall were turned off Monday night to pay homage to the Notre-Dame Cathedral.

Former Montrealer Jennifer Leblanc is staying with a local family as she visits Paris and said that the building means a lot to them and the country.

She walked by the cathedral Monday morning, on her way to Shakespeare and Company, the famous English-language bookstore located within eyeshot of Notre-Dame.

Later in the day, she said she saw "massive billows of smoke, all different colours," and found out the basilica was burning.

"It's a really sad time in Paris," she said.

As a tourist, the structure represents a piece of history to her.

She said she would want to go to the site tomorrow to honour its memory, but isn't sure the area will be reopened to the public then.

In the streets, people are "super silent," said Franck Pierron, a former Montrealer who lives in Paris.

"I've never seen that before," he said.

• Both towers believed safe after fire devastates Notre-Dame Cathedral

A firefighter at the scene said all efforts were being directed at saving the northern tower and the artwork at the back of the cathedral.

Montreal's Museum of Fine Arts posted a painting of the basilica from its collection to its Instagram page with a broken heart emoji as the caption.

"There are a lot of art works inside … it's a real tragedy," Paris Mayor Anne Hidalgo told reporters at the scene.