Ensorcelle comes from the verb ensorceler, meaning 'to bewitch', 'to enchant', or 'to cast a spell on'. It's a beautifully poetic word you won't find in your average textbook.
In the song, the Seine river is personified as a captivating woman. The singer says, "Tellement jolie elle m'ensorcelle" (So pretty she bewitches me), perfectly capturing the magical, enchanting feeling of falling under the spell of Paris and its famous river.
This song is a love letter to a river! French artist Vanessa Paradis sings about the Seine, the famous river that runs through Paris, as if it's a beautiful, confident woman. She describes the river getting out of bed, "Tellement sûre d'elle" (So sure of herself), and being so pretty that "elle m'ensorcelle" (she bewitches me). The song creates a magical, dreamlike version of Paris where the city itself is under the river's spell: "Tu n'es pas saoul / Paris est sous / La Seine" (You're not drunk / Paris is under / The Seine).
The singer feels a deep, personal connection to the river, but she can't quite explain it. The chorus repeats, "Je ne sais, ne sais / Ne sais pas pourquoi / On s'aime comme ça la Seine et moi" (I don't know, don't know / Don't know why / We love each other like that, the Seine and I). It's a mysterious, fated kind of love. The song even takes us to a specific romantic spot, the "Pont des Arts" (Bridge of the Arts), where the singer's heart "vacille" (wavers) as she sees their reflections in the water.