That's because your account is registered in the UK, and you cannot manually yourself, change countries.
If you are now living in France permanently, you'll need to open a new account in France, then everything will show in the correct currency. You'll need to use another email address .
If in France now and wish to do this, log out of this UK site and log into your homesite which is now...
https://communaute.ebay.fr/
Open a new account from there.
@pushcomes