The present invention relates to a method for manufacturing a weakening structure in a decor layer of an airbag cover, said weakening structure not being visible when observed from a viewed side. With the method, a punching tool penetrates into a rear side of the decor layer consisting of leather, said rear side being away from the viewed side, and thereby is simultaneously rotated about its longitudinal axis. A penetration depth of the punching tool which is smaller than the thickness of the decor layer is moreover maintained.