How may I change the database/Tables/Attributes charset using PhpMyAdmin (No SQL statement, only hand-and-mouse actions) ? I only see the option for the Collation (inter-classement).
Changing the collation is what you want to do.
Collations are rules regarding the sort order and search sensitivity. Every collation is based on a certain character set. There is no way to specify the character set separately from the collation.