A process for the preparation of a trichloromethyl-trifluoromethylbenzene of the formula ##STR1## wherein R.sup.1 and R.sup.2 are independently selected from the group consisting of hydrogen, fluorine, chlorine and bromine which comprises contacting a bis-(trichloromethyl)-benzene of the formula ##STR2## wherein R.sup.1 and R.sup.2 have the previously assigned significance with less than 6 mols of anhydrous hydrogen fluoride in the presence of a halogen transfer catalyst.