Montreal firefighters were called to a four-storey apartment building in the Golden Square Mile late Saturday morning after a fire broke out around 10:15 a.m.
Several residents in the Stanley St. building and from surrounding homes were evacuated. About 20 were unable to return home once the fire was put out.
No one was injured.
Police closed the area to traffic for several hours.
The cause of the fire is believed to be electrical, starting on the fourth floor near a thermostat and quickly spreading to the roof.