As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
SHORTLY AFTER T/O GOT AN AVIONICS SMOKE INDICATION ON THE O/H PANEL AK ALONG WITH BOTH ECAM AND CRC. DECLARED EMERGENCY AND RETURNED TO DEPARTURE NO PERCEIVABLE SMOKE ODOR IN THE COCKPIT- NEITHER VISUAL NOR BY SMELL TEST. R & R SMOKE DETECTOR 13WA REF L/P 32502, ITEM 1.