During a pyrotechnic assembly operation held in a basement underneath the city hall, a fireworks shell exploded and triggered the release of all the other fireworks (200 kg) stored onsite, while awaiting the Bastille Day show two days hence (14th July). Fire-fighters arrived with 3 small nozzles to control the incident. It appears that the fireworks preparation team had combined the displays inside the storage room, thus transforming the initial event into something more catastrophic. 4 people were present on the premises: 2 pyrotechnicians and 2 city hall employees. One was seriously hurt, the 3 others sustained minor injuries. As a general rule, experts recommend pyrotechnic products not to be stored on a basement level, but instead in adapted spaces allocated for this purpose. The issue was also raised over how best to train city hall personnel in handling pyrotechnic activities.