A level French is rubbish for a lot of people. You don't learn any really "useful" topics as such (I can't order food for the life of me but if you want the benefits and drawbacks of advertising I've got you covered fam) and I hold the belief that if one is good at gcse and they wish to learn another language in a sort of useful way they maybe shouldn't bother with the A level and look into alternative methods. Of course if you want to do the language at uni you'd be better of taking it to enable you to do that.
A level Biology is a bit weird, everything I learned at gcse turned out to be a bit of a lie. (ribosomes don't "make" proteins as such, mitochondria don't make "energy" as such, there's a lot more bits in a cell than you thought. Strange times.) However it's very good in my opinion, very interesting. There's some sorta chemistry-heavy stuff in bits of it but if you're considering doing chemistry A level anyway that probably shouldn't be an issue for you, it's sorta GCSE level chemistry to an extent.
Chemistry I don't do but the people I know that do it attest that it is very difficult and a number of them claim I should be glad I didn't take it. But I cannot speak from any personal experience on that one, I personally regret doing French instead of chemistry.
Do note I'm only in the first year and haven't done A2 in any of these things.