An apparatus for adjusting the hardness and geometry of seating elements of a motor vehicle seat, in particular for adjusting the curvature and/or width of side bolsters of a seat bottom or a backrest, of an upper rest part of a divided backrest, a lumber support or thigh rest of a seat bottom having supporting wings, the position of which can be changed by way of pivotable actuating elements is provided. The actuating elements are part of an adjustment module for adjusting the seating element, said module comprising a carrying element which can be connected to the seating element and on which the actuating element is pivotably mounted and can be adjusted along a control curve by means of a spindle drive connected to the carrying element.