...if she does the "Charleston" - a dance from the 1920's?
shareI noticed that too! In the little skit that was supposed to show her as a "modern girl," she danced a dance that seemed to date from the so-called "Flapper Era" of 30 years earlier. Kinda' funny in an unintended way.
“No you're not hardcore! Unless you live hardcore!” — The School of Rock
At the time of the film, the Charleston was about 25 years old, more recent to them than the beginnings of punk rock are to us. I can easily imagine a movie today showing a young woman playing punk rock as a comical, light-hearted or humorous way of demonstrating how modern she is.
P.S. An American in Paris is not set in the 1920s, but in the present (post-WW2).
You may as well go to perdition in ermine; you're sure to come back in rags.
Just because the Charleston was born in the 20's doesn't mean it was completely dead. People still danced it into the 40's (if online sources are to be believed. I'm not 80+ years old to have seen it firsthand).
People are still "waltzing" in the form of "slow dancing" and that's how many centuries old?
That is not the question.
The question is "Why use a 30 years old dance to illustrate the fact that she is "modern"?
That always jumped out at me, too. I think of it this way.
The real Lise is not doing anything, including the Charleston. The imaginary Lise that Adam is picturing is doing whatever Adam imagines.
The bit is all about super-positive Henri being bad at describing her in English, jumping from one extreme to another, and cynical Adam picturing whatever pops into his mind.
I always interpreted Adam's picturing her doing the Charleston as just a weirdness of Adam's -- maybe he's picturing what a "modern" girl might have done when he was young, or the last time he pulled his head out of the piano (and being glum) long enough to notice popular culture (other than jazz, which he seems to know).
I could be wrong, but I think that might have been the intent. At the time, audiences would have been ready for a character played by Oscar Levant to be odd, out-of-touch, and possessed of a mind that can go in any weird direction.
BTW, I love how the music matches with the visual in that segment -- arrangements of "Embraceable You" in lots of different styles; bluesy for the sexy part, Classical-ish for the shy part, quasi-Baroque for the reading part, etc.
The monochrome backgrounds, contrasting with her costumes, are great, too.
https://www.youtube.com/watch?v=QKcD-e05HJ8