As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AIRCRAFT WAS NOT GROUNDED. SMOKE - LAVATORY SMOKE MESSAGE MOMENTARILY APPEARED ON ECAM WITH FORWARD LAVATORY OCCUPIED. PASSENGER WAS QUESTIONED ABOUT SMOKING AND DENIED IT. LAVATORY INSPECTED AND NO SIGNS OF SMOKE OR FIRE. NO RECURRENCE THE REST OF FLIGHT. MAINTENANCE PERFORMED SATISFACTORY OPERATIONAL TEST OF THE LAVATORY SMOKE DETECTION SYSTEM PER AMM 26-17-00.