A new process for the preparation of a known 1,3-dimethyl-5-fluoro-pyrazole-4-carboxanilide of the formula ##STR1## in which Ar represents optionally substituted phenyl, which process comprises a) reacting in a first stage, 1,3-dimethyl-5-chloro-pyrazole-4-carbonyl chloride with a fluoride, if appropriate in the presence of a diluent, and b) reacting in a second stage, the 1,3-dimethyl-5-fluoro-pyrazole-4-carbonyl fluoride obtained in this reaction with an aniline of the formula in which Ar has the abovementioned meaning, if appropriate in the presence of an acid acceptor and if appropriate in the presence of a diluent. 1,3-Dimethyl-5-fluoro-pyrazole-4-carbonyl fluoride as a new compound.