A subject-matter of the invention is a process for the preparation of fluoroolefin compounds. It relates more particularly to a process for the manufacture of a compound of formula (I) CF3—CF═CHX in which X represents a hydrogen or fluorine atom, comprising at least one stage of dehydrofluorination of a compound of formula (II) CF3—CHF—CHFX during which the compound of formula (II) is brought into contact with a mixture composed of water and of potassium hydroxide in which the potassium hydroxide is present in an amount of between 58 and 86% by weight.