As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
(CAN)AFTER ENGINE START, ECAM MESSAGE, AFT CARGO SMOKE ALARM ACTIVATED. FIRE EXTINGUISHER BOTTLED DISCHARGED. MAINTENANCE INVESTIGATION UNABLE TO FIND EVIDENCE OF SMOKE OR FIRE IN AFT CARGO COMPARTMENT. FU RTHER INVESTIGATION REVEALED SMOKE/FUMES FROM AIRCRAFT ENGINE ENTERED CARGO COMPARTMENT WHEN CARGO DOOR WAS OPEN CAUSING ALARM TO BE ACTIVATED.