The present invention relates to a composition for dyeing keratin fibres, comprising: at least one fatty substance, at least one surfactant at least one oxidation base, at least one coupler of formula (B3) below and also salts thereof, optical and geometrical isomers and tautomers thereof, and hydrates thereof: (B3) in which R1, R3, R5 represent a hydrogen a C1-C8 alkyl or alkenyl, —SR or —OR a (C1-C4)alkylcarbonyl hydrocarbonyl sulphonic or carboxylic acid R2, R4 represent a hydrogen, a C1-C8 alkyl or alkenyl —OR′ two groups chosen from R1, R2, R3, R4, R5 and borne by adjacent carbon atoms may form, together with said carbon atoms, a ring or a heterocycle which is optionally substituted, and which is optionally interrupted with one or more carbonyl groups at least one of the radicals R1, R3, R5 representing a hydrogen at least one of the radicals R2 or R4 denoting a group —OR′ with R′ representing a C1-C8 alkyl or alkenyl, it being possible for this radical to form, with the carbon atom bearing it, one of the neighbouring carbon atoms and its substituent, a heterocycle at least one alkalinizing agent the fatty substance content representing in total at least 25% by weight relative to the total weight of the composition. The present invention also relates to a process using this composition in the presence of at least one chemical oxidizing agent, and to multicompartment devices suitable for the implementation of the invention.
