Hi, French here but I don't know much about the Paris scene, more the Lyon scene but they're probably close. Regarding the French language: you don't need to be good at it. Just learn enough of it so you can show the locals you tried, and soon they'll be ok speaking to you in English. All coding languages are English-based so everybody knows enough to work efficiently with non French-speaking people. Like the other u…
French here too; regarding language, it's rather annoying when there's one only person who don't speak French at work, forcing everyone else to switch. But if the co-workers are young enough, there shouldn't have too much difficulty for them to speak English. And regarding code, all the variable + comment are usually in English.
I understand that that would be annoying. In your shoes, I'd be annoyed if they didn't even try to learn French.
I find that when I meet French speakers and want to practice, their first instinct is to switch to English. That's very kind, but it doesn't help me. If I was in a workplace in France, I would want people to speak French first, but slow down a little and tell me when I mess something up.
How would that go over in a workplace? Or is it the kind of situation where you speak English because it's the least annoying choice? :)