Hi!
I guess you won't be able to teach sciences until you've become fluent in French. But I think you will probably be able to reach English, more likely in the private schools specialised in language learning. I'm French so I don't have the skills but I have an israelian frind, who stayed 9 years in England. She studied Art but now she is teaching English in schools like "Wall street Institute" and so on... You could also check the international diploms, maybe some are looking for this specific "English speaker teacher".
I would anyway advice you to learn some French before coming in Paris. It will be very helpful in the streets and moreover to get some friends...