What was found
FLT 119, JFK-MSY, UPON LANDING GEAR RETRACTION, RECEIVED "L/G DOORS NOT CLOSED" ECAM. LANDING GEAR WHEELS IND NORMAL, BUT GEAR DOOR IND OPEN. DID NOT CLEAR UPON RECYCLE. RETURNED TO DEPARTURE AIRFIELD. REMOVED AND REPLACED L/G DOOR SELECTOR VALVE (41GA) IAW AMM 32-31-34, OPS CHECK OK, LEAK CHECK OK.