@hube2 you’re right 🙂 Thank you it works !!!
With the field name:
if( $field['name'] == 'footer_code' ) {
return $value;
}
Or with the field key:
$footer_code = get_field_object('footer_code', 'option');
$field_key = $footer_code['key'];
if( $field['key'] == $field_key ) {
return $value;
}