A method for detecting a user's intention to lock or to unlock a door of a motor vehicle, using a detection device integrated into a handle of the door, including an ultra-high-frequency antenna, one face of which is situated close to a second outer locking surface or respectively a first outer unlocking surface of the handle, an ultra-high-frequency antenna matching circuit, an ultra-high-frequency signal generator and an electronic unit. The method includes determining a parameter representative of a ratio between a power of a signal transmitted by the ultra-high-frequency signal generator to the ultra-high-frequency antenna and a power of a signal reflected from the ultra-high-frequency antenna to the ultra-high-frequency signal generator, which powers are measured beforehand, and detecting the intention to lock or respectively to unlock when the parameter is higher than or lower than a predetermined threshold.