What was found
LANDING GEAR, ON FINAL APPROACH, ENROUTE, AT APPROXIMATELY 170 KTS WITH LANDING GEAR HANDLE PLACED IN DOWN POSITION GEAR DOORS APPEARED TO COME OPEN BUT LANDING GEAR DID NOT EXTEND, RECYCLED LANDING GEAR UP THEN DOWN IAW ECAM INSTRUCTIONS AND GEAR CAME DOWN AND LOCKED. MAINTENANCE REMOVED AND REPLACED NOSE LANDING GEAR PROXIMITY SWITCH (37GA) IAW AMM 32-31-73-000-001, OPERATIONAL CHECK WAS GOOD.