Lettre de cachet
From dKosopedia
A lettre de cachet was a form of secret warrant, a letter signed by the King of France and countersigned by one of his ministers, and closed with the royal seal, or cachet. These docuemnts were orders to enforce arbitrary actions and judgements that could not be appealed. As such they were symbols of the abuses of the ancien régime and were suppressed during the French Revolution.