English-language sublet contracts in Germany

I would like to sublet a room in my flat for a few months. Since neither I or my potential flatmate are fluent in German, I would like to write up an English contract between us. Does anyone know if this would legally hold up in Germany?

Your landlord might have to agree before you are allowed to sublet, but that wasnt your question... The language shouldnt be a problem, as long as both sides understand it.

you got to check your contract made with your landlord, if such clause is included.

If you do get the permission to sublet I can help you out with an English contract.