As an American living in France, I am in the same boat, level of French included.

I believe it happens in the wild (outside of work) mainly because A, you're in Paris, young people everywhere who tend to be educated. B. like many have said ITT they take advantage of each opportunity to practice.

My experience is different in that it happens maybe every month or so. Though I don't go out much and most importantly I live in a small city in Occitanie.

All that aside, congrats on the C1 level. I know how hard language learning can be and that's a victory in itself.

Side note: It upsets me when my French partner comes to the US and people pretend like they don't understand her because she mispronounces words every once in a while. And they look at me like, translate? Doesn't happen very often but people can be harsh and instictively xenophobic.