The German licence fee for access to radio and television is called Rundfunkbeitrag.
Update: May 2018
If you paid the licence fee for general public access to radio and television (so called Rundfunkbeitrag), you should inform the fee agency that you are leaving in order to stop your payment. It is recommended to send your cancellation via registered letter and to ask for a written confirmation.
On this official website (link in German) you can find a form that you can use in order to give notice of departure.