3rd Level Domains Redirects

Hi guys, i’m writing all my redirects for my new wordpress site. I’ve a problem. Before that update the site was using third level domains like en.domain.com or fr.domain.com to autotranslate the site with a payed service. Now I’ve changed it and I’ve this url structure domain.com/en/ or domain.com/fr/. How to redirect permantly those domains? I tryed writing on CNAME the new url, but isn’t working. Tryed also to delete it and write a redirect on htaccess but it’s showing not found page. How can i solve?
Thank you!