The invention relates to the use of a plant extract as a cosmetic agent. This extract is obtained from a plant belonging to the genus Citrus, or from hybrids derived from the crossing of plant species, at least one of which belongs to the genus Citrus, as a cosmetic active agent. The invention makes it possible to prevent or retard the appearance of the signs of ageing of the skin or to attenuate the effects thereof and/or to improve or restore the radiance of the skin complexion.