N-[(Pyrimidin-2-yl)aminocarbonyl]benzenesulfonamide of the general formula I ##STR1## where R.sup.1 is methyl or ethyl;R.sup.2 is hydrogen or methyl;R.sup.3 is unsubstituted or substituted alkyl;a group ER.sup.6, in which E is O or S, R.sup.6 being unsubstituted or fluorine-substituted alkyl, with the exception of difluoromethoxy, and, if E is O and at the same time R.sup.5 is trifluoromethyl, R.sup.6 may furthermore be methylsulfonyl, ethylsulfonyl, trifluoromethylsulfonyl, allylsulfonyl or propargylsulfonyl;NO.sub.2 or OH;dialkylaminosulfonyl if R.sup.5 is fluorine;C.sub.1 - or C.sub.2 -alkylsulfonyl which may carry 1 to 3 halogen atoms;R.sup.4 is hydrogen, methyl, ethyl, methoxy, ethoxy, fluorine, chlorine, methylthio, ethylthio or C.sub.1 or C.sub.2 -haloalkoxy; andR.sup.5 is fluorine or trifluoromethyl, and their environmentally compatible salts, processes for their preparation and their use.