The invention relates to microemulsions with an average particle diameter of between 5 and 20 nm and containing (a) between 5 and 50 wt % of at least one alkyl and/or alkenyl oligoglycoside carboxylic acid salt of formula (I): R1O[G]pO[(CH2)mCOO-X+]n, in which R1 represents an alkyl group and/or alkenyl group with between 4 and 22 carbon atoms, G represents a sugar group with 5 or 6 carbon atoms, p represents a number from 1 to 10, m represents a number from 1 to 5, n represents a number from 1 to 5 and X represents alkali, alkaline earth, ammonium, alkanol ammonium, alkyl ammonium or glucammonium, (b) between 5 and 20 wt. % of an oily component and (c) between 0 and 15 wt. % monofunctional and/or polyfunctional alcohols with between 1 and 4 carbon atoms. The sum of the components (a) + (b) amounts to between 10 and 55 wt. % of the total composition.