A security element for an object surface separated by a vertical distance, in particular an object height, from a floor area, includes a longitudinally extending flat support body including a first and second flat side. The first flat side is designed to be placed on the object surface. A presence detector and an evaluation unit are mounted on the second flat side, and the support body is made of a flexible material. The presence detector includes a detection region spatially extending around the presence detector away from the first flat side. The detection region is formed by a near-field region, and the evaluation unit includes an electrical energy storage device. The presence detector forms a measuring unit including an electrical characteristic variable. The presence detector also includes at least two electrically conductive electrodes, the electrodes being formed substantially along the entire longitudinal extent of the support body.