District Chief Michael MacCormac says the fire started in a planter, before spreading to a chair on a 4th floor balcony of the building.
A person on scene used a fire extinguisher before firefighters arrived. When crews got there, they put out the remainder of the fire.
One resident has been displaced and damage was estimated at $15,000.
No one was injured. The Ottawa Fire Service says it appears the fire was accidental.