An explosion at Paris' Palais des Sports arena killed one person and injured 15 more, five of them seriously.
The pyrotechnics blast occurred during a rehearsal of "1789, les amants de la Bastille," a musical about the French Revolution.
A technician was reported to have accidentally ignited the pyrotechnics used for the show.
It is believed that he was using a power tool near the fireworks.
The dead man was technical director Marcus Toledano, 41, who is said to have died of a heart attack when the fireworks were set off.
He was rushed to hospital where he later died.
An explosion caused by the pyrotechnics caused a wall to collapse, injuring some of the cast and crew.
The show has been cancelled because of the blast. The fire took 100 firefighters to put out and a dozen trucks.
Written messages of condolence and flowers were being left at the arena on Saturday.
Culture minister Aurelie Filippetti said that she felt a "great sadness" about the incident.
An investigation has been launched to find out the cause of the tragedy.