As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AIRCRAFT WAS NOT GROUNDED: DURING CRUISE FLIGHT THE MID LAVATORY SMOKE ALARM AND ECAM WARNING ACTIVATED MOMENTARILY (LESS THEN FIVE SECONDS) AND THEN EXTINGUISHED. AFTER LAVATORY INSPECTION BY THE CABIN CREW NO SMOKE SOURCE WAS DETECTED. MAINTENANCE CLEANED AND REPLACED SMOKE DETECTOR FILTER IN MID LAV PER AMM 26-17-00. OPS TEST GOOD.