As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
FLIGHT CREW REPORTED A LANDING GEAR SYSTEM DISAGREE ECAM MESSAGE AND THE LANDING GEAR DOOR WAS NOT CLOSED ECAM WARNING AFTER TAKEOFF. AN EMERGENCY WAS DECLARED AND THE AIRCRAFT RETURNED TO DEPARTURE AND LANDED SAFELY WITH NO FURTHER INCIDENT. THE AIRCRAFT WAS GROUNDED. MAINTENANCE REPLACED THE LEFT MAIN LANDING GEAR PROXIMITY SENSOR 15GA PER AMM 32-31-73 AND ACCOMPLISHED A SATISFACTORY OPERATIONAL CHECK.