A new process for the preparation of 1-fluoro-cyclopropane-1-carboxylic acid of the formula ##STR1## which process comprises a) reacting in a first step, a 1-fluoro-cyclopropyl phenyl ketone of the formula ##STR2## in which R represents hydrogen, halogen, methyl, methoxy, phenyl or phenoxy, with an peroxy compound in the presence of a diluent, andb) reacting, in a second step, the resulting 1-fluoro-cyclopropane-1-carboxylate of the formula ##STR3## in which R has the abovementioned meaning, with a base in the presence of a diluent, and then acidifying the mixture. New 1-fluoro-cyclopropane-1-carboxylates of the above-mentioned formula.