Métamorphosez-moi literally means "transform me" or "metamorphose me." It's a strong and evocative verb that suggests a profound change, much like a caterpillar transforming into a butterfly.
In the context of the song, the singer uses this word to express a deep desire for change, perhaps from a state of sadness or emotional struggle, hoping to be transformed by love or by the enchanting "Belle France" itself. It's a poetic and less common way to say "change me," making it particularly interesting.
"Belle France" turns a love song for a woman into a love song for a whole country. Claudio Capéo introduces "Miss Light" with her morning scents, and he's completely under her spell, even while something in his own life feels broken: "the crank has broken, I will no longer taste the summer smells."
He keeps asking the same question about her: do you know this girl in the white dress, the one who dances? It's a question about a person, but it doubles as a question about France itself, mixing longing, a little guilt, and tears. Calling her "my queen" and "the one who carries the weight of our tears" turns a personal feeling into something closer to a shared, national one.
The chorus keeps circling back to the same short line, "ma belle France," repeated like it's enough on its own to hold onto her.