A multi-layer card-shaped data carrier has a marking layer containing a hidden marking, and a thermochromic cover layer arranged over the marking layer at least in the area of the hidden marking. The thermochromic cover layer is opaque below its change temperature, hides the marking, and is translucent or transparent above its change temperature, enabling viewing of the marking. The thermochromic cover layer is pervious to radiation outside the visible spectral range and the marking layer absorbs radiation energy outside the visible spectral range, so that the hidden marking can be incorporated into the marking layer through the thermochromic cover layer by laser radiation of a wavelength outside the visible spectral range.