Coating zones having guide elevated rails for coating and/or handling robots have walk-in control areas positioned one above the other on the outside of the side walls. In the upper control area, in which control and supply devices for the robots on the elevated guide rails, the side wall slants inward. The load-bearing structures for the elevated guide rails are braced by supporting members extending perpendicular to the line of conveyance of the application objects on or under the floor level or at the ceiling.