A self-boosting, electromechanical friction brake having with a fixed, drumlike brake body in which two rotatable brake rings are disposed, which are rotatable counter to one another via a planetary gear and can be spread apart thereby. As a result of being spread apart, the brake rings are pressed from inside against the brake body and are braked. The friction brake may be sealed off and thus protected it against environmental factors. A lubricant filling is possible, which reduces wear and as a result makes a lifetime brake possible. The brake may be cooled through coolant channels which can be connected via connections to a coolant circulation system of an internal combustion engine of a motor vehicle.