The victims are two adult men and a 15-year-old girl. All three suffered smoke inhalation, and one of the men suffered second-degree burns to his lower body.
A firefighter is also injured. A spokesman for the Montreal firefighters did not have much information about his injury, saying only that the firefighter hurt his eye.
Firefighters received a call shortly before 3:30 p.m. About 40 firefighters were called to the scene. The address of the fire is 5452 Grande Prairies Boulevard.
The fire is believed to have started on the first floor. Twelve people live in the duplex, which has six units.
As of 4:30 p.m., a spokesperson for the firefighters say the fire is under control.
The Red Cross are on the scene.
More to come.