Ten people were forced out into the street after a fire broke out in a three-storey building on Sheppard Street south of Sherbrooke late Monday night.
Nearly 100 firefighters responded to call after the fire, which started on the ground floor, spread throughout the building at around 10 p.m.
Several neighbouring buildings were evacuated a precaution as firefighters doused the flames.
Michel Girard, operations chief with Montreal fire service, said a firefighter was injured and was taken to hospital.
Damage to the building was estimated at $300,000.
The fire appears to have been sparked by an electrical problem.