Treatment system for treating workpieces, in particular for treating vehicle bodies, having a) a conveyor system which comprises a multiplicity of transport trucks by means of which the workpieces are able to be conveyed on a conveyor section that comprises one or a plurality of curved portions, wherein each transport truck comprises a running gear and a fastening installation for at least one workpiece, said running gear and said fastening installation being coupled to one another by means of a connecting installation; wherein b) a running space for the running gear is present along the conveyor section, said running space, by way of a connecting passage in the upward direction, being connected to a conveying space in such a manner that the running gear is movable in the running space and the fastening installation in the conveying space is entrained, wherein the connecting installation extends through the connecting passage and wherein the connecting passage in the curved portion has a curved profile; c) a shielding system having a shielding installation is provided, said shielding installation in a curved portion, with the exception of a movable passage window assembly for the connecting installation of the transport truck, covering the connecting passage when the transport truck is situated in the curved portion; characterized in that d) the shielding installation has a multiplicity of, in particular mutually adjacent, shielding elements, and da) each shielding element by means of a bearing installation is mounted so as to be pivotable about a vertical pivot axis; or db) the shielding elements are fastened to a continuous belt which revolves about at least two revolving rollers which are in each case rotatable about a vertical rotation axis such that a shielding lead and a returning lead are formed; or e) the shielding installation comprises a rotary element which is rotatable about a rotation axis and which defines a shielding ring having an external radius R a or an annular shielding segment having an external radius R a, wherein the external radius R a is larger than the curve radius r of the curved portion in which the shielding installation is disposed; and/or f) the transport trucks entrain one or a plurality of covers which are disposed such that the latter, in the conveying space, are situated above the passage window assembly or opening passage windows. a) a conveyor system which comprises a multiplicity of transport trucks by means of which the workpieces are able to be conveyed on a conveyor section that comprises one or a plurality of curved portions, wherein each transport truck comprises a running gear and a fastening installation for at least one workpiece, said running gear and said fastening installation being coupled to one another by means of a connecting installation; b) a running space for the running gear is present along the conveyor section, said running space, by way of a connecting passage in the upward direction, being connected to a conveying space in such a manner that the running gear is movable in the running space and the fastening installation in the conveying space is entrained, wherein the connecting installation extends through the connecting passage and wherein the connecting passage in the curved portion has a curved profile; c) a shielding system having a shielding installation is provided, said shielding installation in a curved portion, with the exception of a movable passage window assembly for the connecting installation of the transport truck, covering the connecting passage when the transport truck is situated in the curved portion; d) the shielding installation has a multiplicity of, in particular mutually adjacent, shielding elements, and da) each shielding element by means of a bearing installation is mounted so as to be pivotable about a vertical pivot axis; or db) the shielding elements are fastened to a continuous belt which revolves about at least two revolving rollers which are in each case rotatable about a vertical rotation axis such that a shielding lead and a returning lead are formed; or da) each shielding element by means of a bearing installation is mounted so as to be pivotable about a vertical pivot axis; or db) the shielding elements are fastened to a continuous belt which revolves about at least two revolving rollers which are in each case rotatable about a vertical rotation axis such that a shielding lead and a returning lead are formed; e) the shielding installation comprises a rotary element which is rotatable about a rotation axis and which defines a shielding ring having an external radius R a or an annular shielding segment having an external radius R a, wherein the external radius R a is larger than the curve radius r of the curved portion in which the shielding installation is disposed; and/or f) the transport trucks entrain one or a plurality of covers which are disposed such that the latter, in the conveying space, are situated above the passage window assembly or opening passage windows.