A process for the manufacture of fluoroaryl compounds having the following formula, preferably fluorobenzenes or fluorobiphenyles, wherein the fluoroaryl compounds may be substituted or unsubstituted, Rn-Ar-F, wherein Ar denotes a substituted or unsubstituted monocyclic homocyclicaryl or a substituted or unsubstituted homocyclic or nitrogen and/or oxygen containing heterocyclic bicyclic (-Ar-) aryl residue or a substituted or unsubstituted biaryl (-Ar-Ar'-) residue of the said monocyclic aryl and/or bicyclic (-Ar-) aryl residue, wherein Ar and Ar' may be the same or not, preferably wherein Ar is a substituted or unsubstituted phenyl (-Ph-), naphthyl or biphenyl (-Ph-Ph'-) residue, more preferably wherein Ar is a substituted or unsubstituted phenyl or biphenyl residue, Rn denotes one or more substituents selected from the group consisting of hydrogen, nitrogen dioxide, halogen (Hal) except fluorine, a substituted or unsubstituted C1-C4 alkyl, a substituted or unsubstituted C1-C4 alkoxy, preferably a difluoralkoxy or trifluoralkoxy group, more preferably a difluormethoxy or trifluormethoxy group, a substituted or unsubstituted C1-C4 haloalkyl wherein the halogen (Hal) is selected from chlorine (Cl), bromine (Br) or iodine, a substituted or unsubstituted C1-C4 haloalkoxy wherein the halogen (Hal) is selected from chlorine (Cl), bromine (Br) or iodine, comprising the steps of: (a) providing as a starting material a compound of formula Rn-Ar-Hal; wherein Ar and Rn have the above meaning, and Hal denotes a halogen selected from chlorine (Cl), bromine (Br) or iodine; (b) providing HF (hydrogen fluoride) and a catalyst, preferably a halogenation promoting catalyst, more preferably fluorination promoting catalyst; (c) mixing the compound of formula of (a) with the HF and the catalyst of (b); (d) feeding the mixture obtained in (c) into at least one continuous flow reactor with upper lateral dimensions of ≤ 5 mm, or of ≤ 4 mm, the continuous flow reactor being one microreactor and therein carrying out the reaction of formula of (a) with the HF in the presence of the said catalyst to obtain a reaction mixture comprising the compound of formula; (e) withdrawing the reaction mixture obtained in (d) from the said microreactor to yield a compound of formula comprising product preferably a compound of formula product; and (f) optionally purifying and/or isolating the compound of formula product obtained in (e) to yield purified and/or isolated compound of formula. Ar denotes a substituted or unsubstituted monocyclic homocyclicaryl or a substituted or unsubstituted homocyclic or nitrogen and/or oxygen containing heterocyclic bicyclic (-Ar-) aryl residue or a substituted or unsubstituted biaryl (-Ar-Ar'-) residue of the said monocyclic aryl and/or bicyclic (-Ar-) aryl residue, wherein Ar and Ar' may be the same or not, preferably wherein Ar is a substituted or unsubstituted phenyl (-Ph-), naphthyl or biphenyl (-Ph-Ph'-) residue, more preferably wherein Ar is a substituted or unsubstituted phenyl or biphenyl residue, Rn denotes one or more substituents selected from the group consisting of hydrogen, nitrogen dioxide, halogen (Hal) except fluorine, a substituted or unsubstituted C1-C4 alkyl, a substituted or unsubstituted C1-C4 alkoxy, preferably a difluoralkoxy or trifluoralkoxy group, more preferably a difluormethoxy or trifluormethoxy group, a substituted or unsubstituted C1-C4 haloalkyl wherein the halogen (Hal) is selected from chlorine (Cl), bromine (Br) or iodine, a substituted or unsubstituted C1-C4 haloalkoxy wherein the halogen (Hal) is selected from chlorine (Cl), bromine (Br) or iodine, (a) providing as a starting material a compound of formula Rn-Ar-Hal; wherein Ar and Rn have the above meaning, and Hal denotes a halogen selected from chlorine (Cl), bromine (Br) or iodine; (b) providing HF (hydrogen fluoride) and a catalyst, preferably a halogenation promoting catalyst, more preferably fluorination promoting catalyst; (c) mixing the compound of formula of (a) with the HF and the catalyst of (b); (d) feeding the mixture obtained in (c) into at least one continuous flow reactor with upper lateral dimensions of ≤ 5 mm, or of ≤ 4 mm, the continuous flow reactor being one microreactor and therein carrying out the reaction of formula of (a) with the HF in the presence of the said catalyst to obtain a reaction mixture comprising the compound of formula; (e) withdrawing the reaction mixture obtained in (d) from the said microreactor to yield a compound of formula comprising product preferably a compound of formula product; and (f) optionally purifying and/or isolating the compound of formula product obtained in (e) to yield purified and/or isolated compound of formula.