PLZ HELP ME WITH MY STAY IN PARIS!

HELLO everyone, I am new here. Sorry that I cannot type Chinese on this computer, but I am really eager for your help. I am in Italy now and will go to Paris soon. My flight back to Rome is on August 4th, 9.30 am from Paris BVA airport (Ryanair). I have done a little research and know this airport is small and closes at night. My question is that is there any 24-hour shops or McDonalds in Paris where I could stay for a night? Because I do not think I have the budget to afford the accommodation for that night. By the way, I am alone. Will it be safe? And any other information? Any will be fine.

THANK YOU ALL SO MUCH!!!!!!!!!!!!!!!!!!!!!!!!!