As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AIRCRAFT WAS NOT GROUNDED: AT CRUISE FORWARD LAVATORY SMOKE WARNING ECAM ILLUMINATED FOR 3 SECONDS AND WENT AWAY. FLIGHT ATTENDANT CHECKED LAVATORY AND TRASH CAN AND REPORTED EVERYTHING WAS NORMAL. NO SMOKE NO SMELLS. MAINTENANCE RESET THE SMOKE DETECTOR CONTROL UNIT #2 (SDCU) AND ACCOMPLISHED A SATISFACTORY OPERATIONAL CHECK.