An assembly for binding a boot to a ski, including a front retaining element that is releasable when the forces to which the front retaining element is subjected are greater than the prestress value of a first spring, a rear retaining element that is releasable when the forces to which the rear retaining element is subjected are greater than the prestress value of a second spring, the rear retaining element being mounted on a slide, and an electronically controllable additional release device. The additional release device includes a rotatable actuation mechanism, in the form of an electric motor. The additional release device includes a bar fixed to the rear retaining element or to the front retaining element, and is capable of moving longitudinally between an open position and a closed position, in reaction to the actuation of the additional release device.