I've used SMSPVA in the past, back in the day when they only supported Russian numbers.

Seems like they've updated their site quite a lot, as they now also support french numbers. See https://smspva.com/

It's 0.9$ for Whatsapp verification. Note that i don't know what they do with the number after they verified it, as such, i would never use it for anything but throwaway verifications. Using this to verify personal stuff seems like a big nono to me, and i personally wouldn't recommend it. (That goes for any number you buy from anyone online.)