A device for treating objects, wherein a gap is formed between two wall sections of a treatment chamber. At least one respective component of at least one first and one second working device which can move along the gap, extends from an outer region outside of the treatment chamber through the gap into the treatment chamber. A covering assembly seals the gap in the wall of the treatment chamber, apart from a first through opening and a second through opening, through which the component of the first working device or the component of the second working device extend, and which follow a movement of the component of the first working device or the component of the second working device along the gap. A covering band running on the gap is secured to a first and to a second securing side of the first working device, said first and second securing sides facing one another in the longitudinal direction of the gap. A diverting device, directs the covering band from the first securing side to the second securing side of the first working device, and also from the first securing side of the first working device to the second working device, where it is lifted away from the gap using a lifting device and directed past the second working device.