Abstract: A device for the blocking of a catch adjustment device for motor vehicle backrests, with adjustable inclination, that are articulated at a seat portion, the catch adjustment device having a catch gear toothing a catch element that may be brought into engagement therewith in various positions of inclination. When the inclination is being adjusted, the catch member lies out of engagement. The device comprises a control element that is sensitive to inertia, and which triggers blocking of the backrest when the catch lock is released. The control element, which is sensitive to inertia, affects a blocking device that can be activated pyrotechnically, and is provided between an area that is firmly attached to the seat and an area firmly attached to the backrest.