Ara Abrahamian dumped his bronze medal on the floor in protest at the judging in the Greco-Roman wrestling event and was subsequently disqualified from the Beijing Olympics last month.
Abrahamian thought he had beaten Andrea Minguzzi, the eventual gold medallist, in the semi-finals, but the match was awarded to the Italian.
The Swede grudgingly climbed the podium after finishing third in the 84kg class but he left the medal at the centre of the competition mat before stalking off with his fist raised.
"Ara Abrahamian requests that the sanction be limited to a warning," the Lausanne-based CAS said in a statement.
CAS said it usually delivers a decision within four months of an appeal being filed.