As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
HAD A LAVATORY SMOKE WARNING SHORTLY AFTER TAKEOFF. NO SMOKE WAS DETECTED FROM ANY OF THE 3 LAVATORIES IAW INFLIGHT INSPECTION. RETURNED TO DEPARTURE. TESTED THE LAVATORY SMOKE DETECTION SYSTEM IAW AMM. OPS TESTED GOOD, INSPECTED THE LAVATORY TRASH CAN, FIRE EXTINGUISHER AND SURROUNDING AREA FOR FIRE DAMAGE, NO DEFECTS NOTED. COMPLIED WITH NO GO ODI CHECKLIST PROCEDURES AND TSM. OK FOR SERVICE.