A filler coupling for a pressurized gas receptacle comprising a body defining an internal filler circuit between an upstream end designed to be connected to a packaging connector and a downstream end designed to be connected to a receptacle, the coupling comprising an isolation valve that can move relative to a seat between an upstream position for closing the circuit and a downstream position for opening the circuit, said isolation valve being moved to its upstream position by a return member, the coupling also comprising a dust-prevention valve placed upstream of the isolation valve, said dust-prevention valve being able to move relative to the body between an upstream position for closing the upstream end of the circuit and a downstream position for opening the circuit upstream end, said dust-prevention valve being moved to its upstream position by a return member, characterized in that the dust-prevention valve supports a filter interposed on the path of at least a portion of the fluid that travels between the upstream and the downstream of the circuit, the filter being able to move with the dust-prevention valve.