A performance of a theatre show had to be stopped and the area was "cleared immediately" when part of the set collapsed on the audience.
Three people sustained minor injuries in the incident, which happened during Fuerzabruta at the Roundhouse in Camden, last night.
In a statement, the venue said the mishap occurred about half an hour into the evening's show.
Fuerzabruta is an aerial theatre show which has been running at the venue since late December. This is the third visit for this production following runs in 2006 and 2012.
On its website, the Roundhouse says: "Fuerzabruta is an event where worlds collide, where dreams are real and reality takes a back seat. Give in to it, let go and enjoy the spectacular ride."
The production features interaction between the performers and the audience.
London Ambulance attended the scene and treated people who sustained minor injuries.
A spokeswoman said:
"We were called at 7.48pm last night to an incident at the Roundhouse. We sent a duty officer and an ambulance crew to the scene and our staff treated three patients - two men and one woman, all with minor injuries."
She said they were a facial injury, an ankle injury and concussion. They were taken to the Royal Free Hospital.
Just last month, about 10 square metres of plaster from the Grade II-listed Apollo Theatre in the West End plummeted on to the stalls below leaving 80 people injured.