About 20 firefighters were sent to London's Covent Garden on Sunday afternoon when a fire broke out in the market area of the popular tourist site.
More than 100 shoppers and holidaymakers were evacuated and smoke was seen coming from the roof.
People took to Twitter to post pictures of the blaze and firefighters at the scene.
A London Fire Brigade spokesman told London24 that fire engines were sent from Soho, Clerkenwell, Lambeth and Dowgate stations.
"Around 100 people escaped from the building before the Brigade arrived," he said.
"A small amount of the lead flashing on the building was also damaged in the fire."
Robert Clark, who was evacuated from the market, told the BBC: "It looks like it's a kitchen fire that's gone up into the roof."
The fire was under control an hour after firefighters were called and the cause of the blaze is now under investigation.
Raymond Blanc's Covent Garden restaurant banned from serving liver that poisoned diners
Tourists left in the dark after fire causes power cut across Santorini