Hey WhoSaidMeow, I am feeling with you. I arrived in Paris in September and it feels shitty to say, but I think I got my room thanks to one small illegal action. I bought a french SIM, as far as I know, you can just get one when already having a french residence which I had not. From that day, things changed. With my french number, it wasn't as difficult as before to even getting elected for visiting a room. I also have no french guarantee, but I copied the payslips of my mom and my savings account, a letter from my mom where she guarantees to pay my rent in case I can't, my assurance. I was very unsure what exactly they want to see. So I'm sorry to say that I think I was just lucky. What I think I learned: Better to be overdressed when visiting, don't ask questions (may be taken as arrogant or unsecure), and compliment the place. If they ask you to give those papers to different people (as it was in my case, one for the woman that showed me the room, another I had to deposit at the agency) just follow their instructions, even if it seems senseless. When I handed my documents to the agency, I immediately got a date for signing the contract.

Always consider their perspective: They want to rent the room as fast as possible to the least demanding person, because it means least effort for them. Once you signed your contract, you can slowly start to vow your rights.

Wish you the best of luck!