The Galactic Peace Commission was an organisation led by Zanthus Pia in the year 50,000, dedicated to preserving peace in the Galaxy. Zanthus Pia was later assassinated by Ahab and his gang of four Jixen. (TV: The Bounty Hunter)
Ahab referred to this organisation as the "Galactic Peace Assembly", while Zanthus called it the "Galactic Peace Commission", it is unknown if they are different names for the organisation or if it was an error on Ahab's part.