Air carrier Captain reported Ground Personnel approached the aircraft and opened the Forward Cargo Door prior to engine shut down. There were no injuries.

Narrative

Aircraft X ZZZ1-ZZZ. After Landing in ZZZ I proceed into ramp spot for parking gate XX. It is not uncommon to arrive with nobody available to park; so we wait for 1;2;3 ramp to assume their positions before pulling into the gate with safety area clear.As I am slowly moving down the J-line to park...watching Jetway and Guide Man....I notice someone running (off to my right). Person came out of nowhere as was not visible in safety area not wearing any safety vest. I slow a crawl as he runs right under the nose of the aircraft. I lose sight of person and watch the Guide Man motion me to continue; so I slowly continue last few feet. I assume the idiot that ran right under the nose of the aircraft was retrieving the chocks.After I set the brakes..before I shut down #2...ECAM FWD CARGO DOOR OPEN! I immediately shut down #2 then #1; hoping the idiot that popped the door was not sucked into the engine!After shutdown checklist; I called Ramp to advise of the unsafe ramp issues and was told that I should call Operations. Called Operations and was advised they would advise ramp lead.Ramp safety area is insecure in ZZZ! Always either equipment across the line or vehicles crossing in front of aircraft trying to park. Usually waiting for parking crew to show up or crew hunting for wands; or missing 1 of 3 crew. When parking I am focused on Guide Man and cannot continue looking left/right for intrusions to the safety area. In this case I just caught the person running across the J Line out of the corner of my eye. Yet the lead motioned me to continue. After parking brake set I had 10 seconds left on 3 minute clock for shutdown. This is when the ramp crew opened Forward Cargo door with both engines running and beacon on. ECAM FWD Cargo OPEN!I suggest perhaps the entire Parking Crew show up at the same time and be ready for aircraft parking with wands. They should not even approach the cargo doors with engines running beacon on! Have them watch the video of ramp crew sucked into the engine when they got too close! This is an accident waiting to happen. This happens not just in ZZZ but other stations as well. Please review the video at the gate.