"Vous avez l'air d'un môme!"
(You have the air of a kid!)
Here, there's a double meaning involved.
Air is often used in French, and less commonly but definitely in English too, in the sense of a 'melody,' a 'tune.' This is exactly how it's used in, say, that other famous Piaf song "Padam...Padam..." where it's used to refer to the song itself.
If you read 'air' as 'melody' here, then the line might come to mean "You (that is the guy being referred to as Milord) have the tune (song) of... not just a kid, but Piaf herself! (Piaf having been known in her early performing days as La Môme Piaf which means The Kid/Little Sparrow)
Note:
"Vous avez l'air d'un môme!" (You have the air of a kid!)
Here, there's a double meaning involved.
Air is often used in French, and less commonly but definitely in English too, in the sense of a 'melody,' a 'tune.' This is exactly how it's used in, say, that other famous Piaf song "Padam...Padam..." where it's used to refer to the song itself.
If you read 'air' as 'melody' here, then the line might come to mean "You (that is the guy being referred to as Milord) have the tune (song) of... not just a kid, but Piaf herself! (Piaf having been known in her early performing days as La Môme Piaf which means The Kid/Little Sparrow)