The technical director of a Paris musical died of a heart attack after a faulty power tool set off fireworks at an arena on Friday.
Police said Marcus Toledano, 41, was among several people who were caught in a second explosion at the Palais des Sports shortly after 6pm. He was pronounced dead at a hospital.
The second explosion caused a wall to collapse.
Police said five people were seriously injured. They were stage hands who were setting up for an evening performance of 1789, the Lovers of the Bastille.
The show was cancelled as a result of the blasts. It was first shown in Paris last year and has also been performed outside Paris.
The Palais des Sports has a capacity of 4500 and is one of the capital's largest performance spaces. It hosted the premiere of Les Miserables in 1980.