Motor vehicle comprising a partition arranged to separate a passenger compartment from a loading space, and a fastening device for the partition wall, the fastening device comprising: - a guide carriage (11 b, 12 b) arranged to receive the separation partition, - guide rail (11 a, 12 a) arranged to allow the movement of the guide carriage (11 b, 12 b) along a longitudinal of the vehicle, - an upper lock (20a, 20b) blocking the movement of the guide carriage (11b, 12b) along the longitudinal axis, the upper lock (20a, 20b) comprising an elastic stop generating a stress on the guide carriage (11b, 12b) against the guide rail in a second vertical direction perpendicular to the longitudinal axis, the upper lock (40a, 40b) further comprising a locking pin for blocking the movement of the guide carriage (11b, 12b) on the guide carriage guide rail (11a, 12a), and an operating lever arranged to move the locking pin in the second direction, - the fixing device further comprises a lower lock (40 a, 40 b) distinct from the upper lock (20 a, 20 b) and arranged to block the movement of the partition along the longitudinal axis with respect to the body of the vehicle and in a third direction, perpendicular to the longitudinal axis and included in a horizontal plane, characterized in that the operating lever is mounted to rotate and comprises a cam which, during the rotational movement of the operating lever, first displaces the locking axis, and, secondly, exerts an elastic stress which then exerts the stress on the carriage in its turn in the second direction, the operating lever being arranged to compress the elastic stop when the locking axis is in the blocking position of the guide carriage, in order to generate the stress on the guide carriage (11b, 11a). and a fastening device for the partition wall, the fastening device comprising: - a guide carriage (11 b, 12 b) arranged to receive the separation partition, - guide rail (11 a, 12 a) arranged to allow the movement of the guide carriage (11 b, 12 b) along a longitudinal of the vehicle, - an upper lock (20a, 20b) blocking the movement of the guide carriage (11b, 12b) along the longitudinal axis, the upper lock (20a, 20b) comprising an elastic stop generating a stress on the guide carriage (11b, 12b) against the guide rail in a second vertical direction perpendicular to the longitudinal axis, the upper lock (40a, 40b) further comprising a locking pin for blocking the movement of the guide carriage (11b, 12b) on the guide carriage guide rail (11a, 12a), and an operating lever arranged to move the locking pin in the second direction, - the fixing device further comprises a lower lock (40 a, 40 b) distinct from the upper lock (20 a, 20 b) and arranged to block the movement of the partition along the longitudinal axis with respect to the body of the vehicle and in a third direction, perpendicular to the longitudinal axis and included in a horizontal plane, - a guide carriage (11 b, 12 b) arranged to receive the separation partition, - guide rail (11 a, 12 a) arranged to allow the movement of the guide carriage (11 b, 12 b) along a longitudinal of the vehicle, - an upper lock (20a, 20b) blocking the movement of the guide carriage (11b, 12b) along the longitudinal axis, the upper lock (20a, 20b) comprising an elastic stop generating a stress on the guide carriage (11b, 12b) against the guide rail in a second vertical direction perpendicular to the longitudinal axis, the upper lock (40a, 40b) further comprising a locking pin for blocking the movement of the guide carriage (11b, 12b) on the guide carriage guide rail (11a, 12a), and an operating lever arranged to move the locking pin in the second direction, - the fixing device further comprises a lower lock (40 a, 40 b) distinct from the upper lock (20 a, 20 b) and arranged to block the movement of the partition along the longitudinal axis with respect to the body of the vehicle and in a third direction, perpendicular to the longitudinal axis and included in a horizontal plane, characterized in that the operating lever is mounted to rotate and comprises a cam which, during the rotational movement of the operating lever, first displaces the locking axis, and, secondly, exerts an elastic stress which then exerts the stress on the carriage in its turn in the second direction, the operating lever being arranged to compress the elastic stop when the locking axis is in the blocking position of the guide carriage, in order to generate the stress on the guide carriage (11b, 11a).