Four fire engines and around 25 firefighters were called to a fire at an office block on Ladysmith Road in Enfield.
A small part of the ground floor of the three-storey building was damaged by the fire. There were no reports of any injuries.
The Brigade was called at 0456 and the fire was under control by 0540. Fire crews from Enfield, Edmonton and Chingford fire stations attended the scene.
The cause of the fire is under investigation.