A hydraulic control device for at least one hydraulic aggregate of a brake system, and a brake booster control device, interacting therewith, for an electromechanical brake booster of the brake system. The hydraulic control device includes a first control electronics by which at least one motor target quantity that is to be realized by a motor of the electromechanical brake booster can be determined, taking into account a provided brake actuating strength quantity relating to a current actuation of a brake actuating element, and by which a specification signal corresponding to the at least one determined motor target quantity can be outputted to the brake booster control device. The brake booster control device has a second control electronics that, at least in a normal mode, outputs the control signal to the motor of the electromechanical brake booster, taking into account the specification signal outputted by the hydraulic control device.