The invention relates to a filtering device connected between a rectifier module of a variable speed drive and an alternating current power supply network, the filtering device comprising an EMC filter comprising a common-mode inductor having a winding on each phase of the power supply network, the windings being magnetically coupled together. The filtering device comprises a shunt circuit connected in parallel with at least one of the windings of the common-mode inductor, the shunt circuit comprising passive components and making it possible to shunt a common-mode current flowing in the common-mode inductor in a frequency zone about a resonance frequency of the EMC filter.