The incident happened just before 8 p.m. ET on Friday near the intersection of Roger-Pilon and Barnett streets.
A car carrying a man and a woman was struck at least once, but the people were not injured.
The 30-year-old woman, however, was taken to hospital to be treated for shock.
A canine unit dispatched to the crime scene found a gun. It will be sent to a ballistics lab to confirm whether it's the gun used in the shooting.
Const. Simon Delorme of the Montreal police said a suspect was arrested nearby. He described the man as behaving aggressively while being transported to the police operational centre.
Delorme said he calmed down Saturday morning, and he was questioned early in the day by police.
No charges have yet been laid.