The title is.
I don't think the lyrics are.
I can distinguish a couple words in there, but whole sections of the song sound either like a made up language or some language I have no idea.
That, or the pronunciation is so distorted it's impossible to recognize.
Like she clearly says "La vie boheme, la vie *something something* la *something* merci".
At this point, it's easy to fool myself in believing this is actual french or if I'm imagining it and trying to bring made-up words to a language I know.
(this happens often in Emi Evan's chaos language)
The presentation of the single doesn't refer to any existing song or poem, so it's probably an OC.
This leads me even more to believe it's not French interspersed with something else.
Good song though, thanks for making me discover this!