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 "LAVATORY SMOKE" ECAM ALERT LASTED APPROXIMATELY 5 SECONDS. FLIGHT ATTENDANTS CHECKED AFT LAVATORY. NO EVIDENCE OF SMOKE FOUND. PERFORMED OPERATIONAL TEST OF THE LAVATORY SMOKE-DETECTION SYSTEM, PER AMM TASK 26-17-00-710-001-A. OPERATIONAL CHECK GOOD.