Four fire engines and 21 firefighters and officers were called to a fire at a takeaway restaurant with flats above in High Street, Bromley.
Part of the ducting from the ground to the second floor and part of the ground floor were damaged by the fire. Crews ventilated three of the first floor flats as they were smoke-logged.
Seven people left the building before the Brigade arrived. There were no reports of any injuries.
The Brigade was called at 0338 and the fire was under control at 0531. Fire crews from Bromley, Beckenham, Lee Green and Lewisham fire stations attended the scene.
The cause of the fire is under investigation.