The man was pronounced dead at the scene after emergency services workers tried to revive him. (CBC)

The Montreal Police major crimes unit is investigating the death of a man in his 40s, found in the city's Plateau neighbourhood.

Constable Anthony Cantelmi said officers were called to Maguire Street near the corner of Henri Julien Avenue at about 11:30 p.m. Friday.

Cantelmi said officers found the man unconscious with blood on his face.

"Police officers tried to revive him. Ambulance technicians who arrived on site attempted different things to revive him but they were unsuccessful and he was declared dead on the scene," he said.

Witnesses told police the victim was fighting with another man earlier in the evening.

Cantelmi said police are treating the death as suspicious and an autopsy will be performed to determine how the man died.