Firefighters were called to the building, which houses a beauty salon and a massage therapy clinic as well as apartments, just after 1 a.m.
One of the building's occupants reported hearing an explosion before fire quickly overtook the structure.
All tenants were able to get out of the building and no injuries were reported.
Firefighters from several communities were dispatched to extinguish the flames.
Cpt. Yannic Parent of the Richelieu Saint-Laurent police said it appears the fire was deliberately set.
"The fire department, they found some clues about some accelerant and they began to think that maybe this was something criminal," he said. "This is why we are still investigating that question."