@Omar_203
Okay so you have internal form with users that are logged into to M365. Your form has a radio selection to selct either FR or EN. I think you need tow sections of the flow, ie.e a paralle branch with an if satement in each branch to slect either EN or FR and then manually compose the email that way to send to them. The only thing that might not be in either language is the dynamic content of the email.
Anyway I wil probably not be able to help much more than the above. Sorry.
Regards,
Andrew
Do you users have their default language set in their profile. If they do can you then not set up a parralle branch with the IF to then select languiae of the email