Device for detecting a user's intention to lock or unlock a motor vehicle door and associated door handle

A device for detecting a user's intention to lock or to unlock a motor vehicle door. The device contained in a watertight housing, integrated into a non-watertight handle, the lower part of which includes drainage holes, a part of the housing being immersed in water. The device including: a capacitive approach and/or contact detection sensor, having at least one detection electrode, a variable detection capacitance representative of the approach of the user's hand, a charging/discharging capacitor Cs, and a protective electrode Ep situated in the part of the housing that is immersed in water, electrically coupled to the detection electrode and connected to a terminal of the charging/discharging capacitor Cs such that the protective electrode Ep is simultaneously at the same potential as the terminal of the charging/discharging capacitor during the various steps of charging/discharging the detection capacitor and the charging/discharging capacitor that are necessary to estimate the detection capacitance.