A four-alarm fire ripped through a building at the corner of De Maisonneuve Blvd. and Bishop St. downtown Wednesday morning.

The fire broke out in the ventilation system of Monteiro restaurant on Bishop St. and charred the three-storey building.

"The fire started in the ventilation ducts. In these ducts, of course, there's always some grease that come from the ventilation from the restaurant," said Louise Desrosiers, fire prevention chief. "We're going to have to investigate what did happen to make sure it doesn't happen again."

More than 40 fire vehicles and 100 firefighters fought the blaze, which is now under control.

None of the nearby Concordia University buildings had to be evacuated.

No one was injured.

Drivers were advised to avoid the area throughout the early afternoon – traffic lights were out and cars faced heavy congestion.

Desrosiers said prevention is key.

"For a restaurant, it's always (important) to make sure there's some maintenance to be done to… ducts every six months, and for restaurants to make sure they have two exits and fire extinguishers," she said. "Make sure that all your exits are safe so you can evacuate as fast as possible."