A concertgoer at the Hammerstein Ballroom fell from a balcony last night during a performance by the French electronica duo Justice.

Witnesses at the West 34th Street site said the man was gripping the ledge for dear life before plummeting at around 10:30 p.m.

The unidentified victim, who was conscious after the fall, was not seriously injured, the FDNY said.

“It happened pretty quick,” said a witness, Michael Bird. “He fell into a group of people below him. I thought he was killed initially.”

Another concertgoer, Anthony DiMieri said, “I heard a loud thud and turned around to see a group of people attempting to help some guy stand.

“Everyone around me was staring at the ground floor. I saw people struggling to help the guy stand, but his legs were giving out beneath him. They were probably broken.”