Greater Sudbury Police Services are calling Wednesday night's incident at the New Sudbury Shopping Centre "isolated" and have no reason to believe the public is in danger.
Police say that a 45-year-old man was hit with pepper spray or mace by two suspects near the bathrooms at the shopping centre.
One of the suspects was wearing a red hoodie, black jacket and jeans. The other wore a blue baseball cap, plaid shirt and jeans, police said.
There have been no other reports of similar attacks before this incident or since, police said.
The victim was treated by EMS and later released from hospital.
Staff Sergeant Marc Brunette said police are still searching for a motive behind the attack. The investigation has been turned over to the criminal investigations division, who are reviewing video footage from the time of the incident.