The invention relates to a method for preparation of fluorinated aromatic compounds from the corresponding amines by replacement of the amino group with a fluorine atom. The method of preparation of a fluoroaromatic compound from an aromatic compound with at least one amino group on the aromatic ring is characterized by the reaction of said aromatic amine compound with a nitrosating agent in the presence of a source of boron trifluoride in an organic medium, and carrying out a thermal treatment of the reaction medium comprising the diazonium salt thus obtained to give the fluoroaromatic compound directly by decomposition of the diazonium salt without intermediate isolation thereof. |