A device for assisting with the parking of a vehicle within a parking space provided with at least one lateral wall (21, 22) having longitudinally distributed geometric features, said device being capable of equipping a vehicle (1, 2), characterized in that it comprises at least: - a first sensor placed on the side of said vehicle facing the entrance of said space, the measuring beam of said sensor scanning said space, said sensor making measurements of the distance and orientation of said vehicle with respect to said space based on the reconstruction of a cloud of points belonging to the surface of said walls (21, 22); - a series of sensors placed on the lateral sides of said vehicle that are intended to measure the distance from said sides to said lateral walls (21, 22), the measuring beams of said sensors scanning said inner walls (21, 22); - processing means calculating the position and the relative orientation of said vehicle with respect to said walls in at least three separate phases: - a phase of approaching said space in which, said walls being scanned by the measuring beam of said first sensor, the relative position and orientation are calculated with respect to the position and orientation of a general form of said walls deduced from said cloud; - a phase of entering said space in which the position and the relative orientation are at least calculated with respect to the position and orientation of simple geometric forms deduced from said cloud, as a function of said geometric features; - a phase of advancing into said space in which the processing means calculate a relative position and orientation by comparing said cloud with a memorized model of said walls and calculate another position and another relative orientation based on the distance measurements made by the sensors of said series; said processing means comprising a data fusion module that carries out spatio-temporal filtering of the relative position and orientation calculations produced from the various sensors (30, 31), the calculations thus filtered giving information on the position and orientation of said vehicle in order to control its movement. - a first sensor placed on the side of said vehicle facing the entrance of said space, the measuring beam of said sensor scanning said space, said sensor making measurements of the distance and orientation of said vehicle with respect to said space based on the reconstruction of a cloud of points belonging to the surface of said walls (21, 22); - a series of sensors placed on the lateral sides of said vehicle that are intended to measure the distance from said sides to said lateral walls (21, 22), the measuring beams of said sensors scanning said inner walls (21, 22); - processing means calculating the position and the relative orientation of said vehicle with respect to said walls in at least three separate phases: - a phase of approaching said space in which, said walls being scanned by the measuring beam of said first sensor, the relative position and orientation are calculated with respect to the position and orientation of a general form of said walls deduced from said cloud; - a phase of entering said space in which the position and the relative orientation are at least calculated with respect to the position and orientation of simple geometric forms deduced from said cloud, as a function of said geometric features; - a phase of advancing into said space in which the processing means calculate a relative position and orientation by comparing said cloud with a memorized model of said walls and calculate another position and another relative orientation based on the distance measurements made by the sensors of said series; - a phase of approaching said space in which, said walls being scanned by the measuring beam of said first sensor, the relative position and orientation are calculated with respect to the position and orientation of a general form of said walls deduced from said cloud; - a phase of entering said space in which the position and the relative orientation are at least calculated with respect to the position and orientation of simple geometric forms deduced from said cloud, as a function of said geometric features; - a phase of advancing into said space in which the processing means calculate a relative position and orientation by comparing said cloud with a memorized model of said walls and calculate another position and another relative orientation based on the distance measurements made by the sensors of said series;