A 33-year-old woman dining at a sushi bar on Peel Street was killed instantly when she was struck by a concrete slab. The victim's husband, 33, lost some fingers and was treated for severe shock. (CBC)

The Régie du bâtiment and the City of Montreal have launched an investigation into the death of a woman who was struck and instantly killed by a piece of falling concrete Thursday evening.

The 33-year-old was dining with her husband at the Mikasa Sushi Bar when a slab of concrete fell off a hotel on Peel Street, near the corner of De Maisonneuve Boulevard.

A waiter at the restaurant said the couple was celebrating the woman's birthday, and they requested the table in the corner of the atrium.

A slab of decorative concrete came crashing through the atrium window of the restaurant, located on the ground floor of the Marriott Residence Inn, from 17 storeys above.

A slab of decorative concrete fell 17 storeys from the Marriott Residence Inn, crashing through the atrium window of Mikasa Sushi Bar on Peel Street. (CBC)

The woman was pronounced dead at the scene.

Montreal police said the victim's husband, also 33, lost some fingers and was treated for severe shock.

"He may have lost a few fingers, but he's in hospital in a stable state," said Const. Olivier Lapointe.

Lapointe said a section of Peel Street, which is in the heart of the city, was expected to remain closed for several hours as a precaution while the fire department inspected the building.

It's not clear what caused the 135-kilogram slab, about one metre by 1½ metres, to come off the side of the building, Lapointe said. Fire officials said they suspect a weld holding the slab of concrete might have broken due to water infiltration.

Ronald Dubeau, deputy chief of the Montreal fire department, said the hotel's owners have been asked to bring in their own inspectors.

“The engineer representing the owner will have to present a schedule for inspection to the Régie du bâtiment and borough also. And if it’s acceptable by both of them, they will have to start the visual and technical inspection of the panel,” said Dubeau.

The Régie du bâtiment is the Quebec authority set up to ensure the proper construction of buildings in the province.

Police said it looks as though this was an accident and they don't suspect foul play, but police and city engineers as well as the fire department continued to investigate the scene Friday morning.

Police said Peel Street would be shut down between De Maisonneuve Boulevard and Sherbrooke Street for most of Friday, and potentially over the weekend.

with files from The Canadian Press