As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
FLT 396 MCO-LGA, AIR TURNBACK TO MCO DUE TO AUDIO SMOKE IN LAV E. UPON INSPECTION THERE WAS NO SECONDARY VISUAL SMOKE OR SMOKE SMELL. THIS WAS ALSO WITHOUT ECAM INDICATION IN THE COCKPIT. REMOVED AND REPLACED LAV E SMOKE DETECTOR PER AMM 26-17-00. OPS CHECK OK.