What was found
(CAN) JUST AFTER DEPARTURE CLIMBING THROUGH 2000 FT, FLIGHT EXPERIENCED AN "AFT CARGO SMOKE" WARNING. THE ECAM WAS FOLLOWED AND THE WARNING CHANGED TO "SMOKE DETECTOR FAULT". A PAN PAN WAS DECLARED WITH ATC WITH A REQUEST TO RETURN TO THE AIRPORT WHERE AN OVERWEIGHT LANDING WAS CARRIED OUT. ERS MEET THE FLIGHT ON LANDING AND FOLLOWED THE AIRCRAFT TO THE GATE. THERE WAS NO ADVERSE PASSENGER REACTION. DUTY PILOT, FLIGHT SAFETY, IFS AND MAINTENANCE CONTROL ADVISED. R7R SDCU IAW AMM 26-17-34-000-001-A, CKS GOOD, NO FAULTS NOTED.