1. A device for analyzing a gait of a person, the device comprising: a magnetometer for fastening to a tibial segment of said person, in order to generate a signal representative of at least one projection onto a sagittal plane of an ambient magnetic field in which the magnetometer is immersed; and signal processor means for identifying instants that are characteristic of the gait of said person solely by identifying particular points in the signal generated by the magnetometer as a function of time, wherein said instants that are characteristic of the gait of said person comprise at least one selected from a group including a toe-off and a heel-strike instant.