A fire broke out in a block of flats on Beaconsfield Road, Enfield EN3 Tuesday morning. Part of the lobby on the 10th floor was damaged by fire.
A woman and two children were treated by ambulance crews for smoke inhalation.
The Brigade was called at 0924 and the fire was under control at 1152.
Five fire engines and 31 firefighters and officers from Enfield, Edmonton and Chingford stations were at the scene.
The police were also called and the cause of the fire is under investigation.