In Essonne, the warning sirens will exceptionally sound for two consecutive days, on December 4 and 5, 2024. This double sound signal is linked, on the one hand, to the monthly siren test, usually scheduled for the first Wednesday of the month, and, on the other, to a civil protection exercise organized by the prefecture. The exercise, scheduled for Thursday, December 5, is designed to test the effectiveness of crisis management systems and raise public awareness.