As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
(CAN) RT AFTER DEPARTURE THE F/A ADVISED THE CREW THAT SMOKE WAS PRESENT IN THE CABIN ALONG WITH AN ELECTRICAL SMELL. ACFT RETURNED TO DEPARTURE AIRPORT. EMERGENCY WAS DECLARED. F/A TURNED OFF CABIN LIGHTS AND ODOR STARTED TO CLEAR. CREW REPORTED WHEN MAINTENANCE GOT ON THE ACFT THEY TURNED THE LIGHTS BACK ON AND THE BURNING ODOR STARTED TO COME BACK.