Substituted N-phenyl- and N-heteroarylalkylcarbamates of the formula I ##STR1## in which Q is a group ##STR2## R is halogen, trifluoromethyl, cyano, nitro or C.sub.1 -C.sub.3 haloalkoxy;Z is hydrogen or halogen; orZ and R together in the 2- and 3-position of the phenyl ring form a group --OCF.sub.2 O--;R.sub.1 is C.sub.1 -C.sub.5 alkyl;R.sub.2, R.sub.3, R.sub.4 and R.sub.5, independently of one another, are hydrogen, methyl or ethyl;X is oxygen, sulfur, --SO-- or --SO.sub.2 --;Y is hydrogen, halogen, C.sub.1 -C.sub.3 alkyl, C.sub.1 -C.sub.3 haloalkyl, C.sub.1 -C.sub.3 alkoxy or cyano;n is 0, 1 or 2;n.sub.1 is 0 or 1; andm is 0 or 1,with the proviso that m is 1 if Q is group (1) or (2);and the diastereomers and enantiomers thereof,exhibit pre- and post-emergence herbicidal properties. The preparation of these compounds and their use as herbicidally active ingredients are described.