Four fire engines and around 25 firefighters were called to a fire at a flat on Birkenhead Street in King's Cross.
Part of a ground floor flat and the reception area of a six-storey block of flats were damaged by the fire. One man was assisted from the flat by a member of the public before the Brigade arrived. He was assessed at the scene by London Ambulance Service crews.
The Brigade's 999 Control Officers took 28 calls to the blaze.
The Brigade was called at 1645 and the fire was under control by 1757. Fire crews from Islington, Kentish Town and Soho fire stations were at the scene.
The cause of the fire is under investigation by the Brigade and the Metropolitan Police Service.