I probably won’t be active in the French course much, but mini lessons like this are so fun for any language, imho 😀 Especially if it’s presented later on in the course as a sort of optional reward (and also, probably more important, so you can tell the difference between slang and proper wording). Honestly, would love this for lots of different themes, too — slang, internet acronyms, proverbs, culturally relevant holidays. 

I can also help with French (native speaker)

I love this idea and would love to have this for German. This would be great even as a separate course.

I learned German growing up, but moved to the US when I was young. I can still read and speak it relatively fluently, but I get very self-conscious in non-professional settings because I missed talking to people casually while growing up.

Doing the beginnings of the German course on Duolingo was a slog because I already knew all the intro stuff, so having it separate or at least integrated relatively early would be very helpful for me.

Would the awesome phrases (quoicoubeh, apagnan, crampté, etc.) qualify?

I think it’s a great idea, slang is part of the everyday language and mastering it is very important. Plus it’s fun, especially verlan

Would also love to help with that!

I would love there being options for slang and even suggest idioms. It not only makes the learner closer to native speakers, it connects you to a part of the culture.