Police were called on Monday, 10 July at 00:10 hours to Camden Lock Market following a report of a building fire.
The London Fire Brigade (LFB) were already on scene when officers arrived.
No one was reported injured and the LFB have brought the fire under control.
Road closures are currently in place at Chalk Farm Road junction with Hartland Road, NW1 and south up to Hawley Crescent.
The cause of the fire is not yet known.
The emergency services remain on scene and enquiries are ongoing.