Abstract: A booth for applying a powdered coating to the surfaces of workpieces in which a clean gas zone is joined to the coating zone via the rear wall, which is connected to an extractor fan. Located in a recess of the rear wall is a frame-like structure, the outer frame of which is split up into individual areas by means of frame cross-members each area receiving a filter element, which is housed in an interchangeable cassette, and consisting of a continuous zig-zag shaped or wave-shaped surface-membrane filter strip. Each area of the frame is covered in a leak-proof manner by a protective hood in hood space in an oblique manner towards the coating zone and detach the excess powder attached to the membrane applied thereon, which is diverted through a slat-type screen down to the floor of the booth and into a powder container. Thorough cleaning can be effected by a second cleaning device arranged in the coating zone or after removal of an interchangeable cassette from the booth.