Abstract: The invention relates to a method for checking the regulation state of a frequency-stabilised laser system comprising a laser (2). At least one first sidebrand frequency VHF is modulated to the laser beam (1) of said laser, the laser beam being guided through an absorption material (13) comprising a plurality of absorption lines in a detuning region of the laser (2), said absorption lines being arranged at different distances from each other. The laser frequency VL is detuned and, as a regulation signal for the laser frequency VL, it is determined whether there has been an absorption in the absorption material.