RATP runs Paris public transport, including the Metro, RER trains, buses and trams, and its short announcement chime is heard by millions of passengers every day across the city. Outside France, the sound spread through travel videos, social media clips and memes, where creators use it as shorthand for Paris itself without needing a caption or landmark. Its familiarity is the point: even people who have never visited Paris often recognise the tone from films, vlogs and online jokes, which keeps it popular as a quick, instantly readable audio cue.