As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
FLIGHT 735 RECEIVED LAVATORY SMOKE INDICATION ON ECAM AT GATE. FLIGHT ATTENDANTS REPORTED SMOKE COMING FROM MIDDLE LAVATORY. PERFORMED SATISFACTORY BITE TEST OF LAVATORY SMOKE DETECTION SYS & INSPECTED LAVATORIES. OPERATIONAL CHECKED OK.