The invention relates to novel substitued aryl sulphonyl(thio)ureas of formula (I) and salts thereof, in which: A is nitrogen or a CH group; Q is oxygen or sulphur; R1 is hydrogen, halogen or possibly substituted alkyl, alkoxy, alkylthio, alkylamino, dialkylamino, cycloalkyl, cycloalkyloxy or heterocyclyloxy; R2 is hydrogen, halogen or possibly substituted alkyl, alkoxy, alkylthio, alkylamino, dialkylamino, cycloalkyl, cycloalkyloxy or heterocyclyloxy; R3 is hydrogen or possibly substituted alkyl; R4 is possibly substituted alkyl, alkoxy, alkenyl, alkinyl, alkenyloxy, alkinyloxy, cycloalkyl, cycloalkyloxy or cycloalkylalkyl; and R5 is hydrogen, formyl or possibly substituted alkyl, alkylcarbonyl, alcoxycarbonyl, alkylsulfonyl, alkenyl, alkynyl, cycloalkyl, cycloalkylcarbonyl, cycloalkylsulfonyl or heterocyclyl; except for the compound N-(4,6-dimethyl-pyrimidin-2yl)-N'-(2-(1,1,2,2-tetrafluorethoxy)-6-methyl-phenylsulfonyl)-urea. Process for producing the novel compounds and their use as herbicides.