The invention relates to a method for reducing common-mode current flowing between the internal ground of an electrical circuit, in particular an electrical circuit of a motor vehicle, and the earth, when electrical energy is exchanged between an electrical energy storage unit of the electrical circuit and an external electrical energy source to said circuit. The method is such that: • an electrical quantity that is at least a function of said common-mode current is applied at an injection point of the circuit using an electronic component, said electrical quantity being applied so as to reduce the common-mode current; • the value of the common-mode current is obtained using a measurement device (124) comprising: - a magnetic toroid (128) configured to be traversed by an electrical line through which said electrical energy is exchanged, said electrical line forming a primary winding (127); - a secondary winding (130), wound around said toroid (128), for generating a magnetic flux from a reference current; - an oscillator (132) for generating the reference current through the secondary winding (130), the reference current being configured to saturate said toroid (128); the common-mode current corresponding to the value of the current in the electrical line obtained from the average value of the current in the secondary winding (130) over an oscillation period running through a complete cycle of magnetization and demagnetization of the toroid (128).
