As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AIR TURNBACK - ON CLIMB-OUT, FLIGHT CREW REPORTED A NR 2 AIR CONDITIONING PACK OVERHEAT ECAM MESSAGE. NR 1 PACK WAS ALREADY ON MEL. RETURNED TO SEA AND DECLARED AN EMERGENCY. AIRCRAFT LANDED WITHOUT INCIDENT. REPLACED NR 2 AIR CONDITIONING PACK CONTROLLER.