Montreal police said the incident happened at around 3:35 a.m. near the intersection of de l'Esplanade Avenue.
Police said two men were walking down the street and toppling over garbage cans before they allegedly broke the window of the store and threw a burning object inside.
The men then fled the scene.
"Police officers were actually patrolling on Fleury when the event took place so they rapidly arrested the gentlemen," said Const. Yannick Ouimet.
Montreal firefighters were called to put out the flames, which spread to the roof of the building and a neighbouring residential and commercial building.
No one was injured and no damage estimate has been released.
Police said they're still interviewing the men detained to determine if charges will be laid.