Déambuler is a poetic verb that means 'to wander' or 'to stroll'. It suggests walking without a specific destination, perfectly capturing a feeling of being lost in thought.
In the song, Slimane sings "Je déambule seul dans le métro" (I wander alone in the metro). This word paints a vivid picture of his loneliness and sorrow as he drifts aimlessly through the city, consumed by his 'douce souffrance' (sweet suffering).
This song throws you right into the middle of a massive heartbreak. The singer feels completely lost without someone, calling himself "un être sans importance" [a being without importance] and admitting, "Sans lui, je suis un peu paro" [Without him, I'm a bit paranoid/crazy]. His life has become "un décor qui brille / Vide de sens" [a shiny set / Empty of meaning]. To cope with this "peine immense" [immense sorrow], he has one solution: to dance.
But this isn't a fun night out. It's a desperate, almost magical act. He says, "Je remue le ciel le jour, la nuit / Je danse avec le vent, la pluie" [I move the sky day, night / I dance with the wind, the rain]. He uses the entire city of Paris as his stage, letting go and trying to fly away from his pain. It’s a powerful image of someone trying to escape their own suffering by dancing so hard they shake the heavens.