Hi, I'm in Year 12 and am studying Geography, Economics and English Lit. I was also taking Psychology but dropped it.
I can't talk on the behalf of French however, my friend takes it and she says that it's extremely difficult. I will say that if you really enjoy French and are good at it then you should be fine, she certainly is.
Psychology really surprised me, I thought it would be my favourite subject when I picked my options but ended up not enjoying it.
Geography I'm currently enjoying and am doing well at so not to be biassed but if you are good at it then I definitely recommend it.
My advice would be to take four options for the first month of A-Levels, especially if you can't decide between French and Psychology. It may seem like a lot of work at first, but just remember that you are able to drop the fourth at any time. Taking four seriously helped me as it meant I didn't miss out on any content by having to switch subjects.
Good luck!