The present invention relates to a cosmetic or dermatological composition in emulsion form, comprising, in a physiologically acceptable support: a) at least one aqueous phase and b) at least one oily phase, and c) at least one merocyanine compound of formula (1 ) or one of the E/E- or E/Z- geometrical isomer forms thereof, in which: R is a C1-C22 alkyl group, a C2-C22 alkenyl group, a C2-C22 alkynyl group, a C3-C22 cycloalkyl group or a C3-C22 cycloalkenyl group, the said groups possibly being interrupted with one or more O, and d) at least one emulsifying system containing at least one gemini surfactant. Another subject of the present invention consists of a non-therapeutic cosmetic process for caring for and/or making up a keratin material, comprising the application, to the surface of the said keratin material, of at least one composition as defined above. The invention also relates to a non-therapeutic cosmetic process for limiting the darkening of the skin and/or improving the colour and/or uniformity of the complexion, comprising the application, to the surface of the keratin material, of at least one composition as defined previously. The invention also relates to a non-therapeutic cosmetic process for preventing and/or treating the signs of ageing of a keratin material, comprising the application, to the surface of the keratin material, of at least one composition as defined previously.
