The sound comes from the door-closing warning system used on trains of the Paris metro, where a buzzer alerts passengers to stand clear before the doors shut. Commuters hear it countless times a day, and visitors often remember it as one of the distinctive sounds of travelling through the French capital. Online, short clips of the buzzer have circulated on soundboards and in travel and comedy videos, where creators reuse it to recreate a station atmosphere or to mark a hurried departure. Its familiarity keeps it useful long after a trip ends.