No one was hurt in the incident.
The cars were parked near the Signa-Plus offices on Bergar Street in the Chomedey neighbourhood.
Authorities said the vehicles belong to individuals and not to the company.
Firefighters said they found gas cans along with safety flares that were most likely used to light the fire.
Emergency services were also called to Montreal North around 2 a.m. to extinguish another fire in a car on Allard Street.
Police reported that firefighters could smell accelerant and and that more clues point towards a criminal fire.
No one was arrested in either cases.