para -Aminophenol compound of formula, the addition salts thereof with an acid and the solvates thereof: in which: • R represents a hydrogen or halogen atom; a C 1 -C 4 alkyl radical; a carboxyl radical or a (C 1 -C 4)alkoxycarbonyl radical; • Z1 is an oxygen atom or a group NR2; • R2 is a hydrogen atom or a linear or branched C 1 -C 4 alkyl radical, a benzyl radical or an acetyl radical; • R1 is a saturated, linear or branched C 1 -C 10 alkyl radical, which is substituted with or interrupted by a cationic radical, optionally interrupted by one or more oxygen atoms and/or by one or more groups NR2, optionally substituted with one or more radicals chosen from hydroxyl, alkoxy or C 1 -C 4 hydroxyalkyl radicals; or • R1 is a saturated, unsaturated or aromatic cationic 5- to 8-membered heterocycle optionally substituted with one or more radicals chosen from C 1 -C 4 alkyl, hydroxyl, C 1 -C 4 alkoxy, amino, (C 1 -C 4)alkylamino, di(C 1 -C 4)alkylamino, thio, (C 1 -C 4)alkylthio, carboxyl, (C 1 -C 4)alkylcarbonyl, sulfonyl, amido or C 1 -C 4 hydroxyalkyl radicals; and when Z1 represents NR2 then ▪ R1 and R2 may form, together with the nitrogen atom to which they are attached, a saturated or unsaturated cationic 5- to 8-membered heterocycle optionally substituted with one or more radicals chosen from C 1 -C 10 alkyl radicals and hydroxyl, C 1 -C 4 alkoxy, amino, (C 1 -C 4)alkylamino, di(C 1 -C 4)alkylamino, thio, (C 1 -C 4)alkylthio, carboxyl, (C 1 -C 4)alkylcarbonyl, sulfonyl, amido and C 1 -C 4 hydroxyalkyl radicals, it being possible for this heterocycle to contain one or more heteroatoms chosen from N or O, preferably N; or ▪ R1 and R2 may form, together with the nitrogen atom to which they are attached, a saturated or unsaturated noncationic 5- to 8-membered heterocycle substituted with a cationic radical and optionally substituted with one or more radicals chosen from C 1 -C 10 alkyl radicals and hydroxyl, C 1 -C 4 alkoxy, amino, (C 1 -C 4)alkylamino, di(C 1 -C 4)alkylamino, thio, (C 1 -C 4)alkylthio, carboxyl, (C 1 -C 4)alkylcarbonyl, sulfonyl, amido and C 1 -C 4 hydroxyalkyl radicals; • An - represents an anion or a mixture of anions which are organic or inorganic and are cosmetically acceptable, wherein the expression "cationic radical" means any linear or branched or heterocyclic radical comprising a quaternary ammonium, and "cationic heterocyle" means a 5- to 8-membered heterocycle in which one of the ring members is a quaternary ammonium • R represents a hydrogen or halogen atom; a C 1 -C 4 alkyl radical; a carboxyl radical or a (C 1 -C 4)alkoxycarbonyl radical; • Z1 is an oxygen atom or a group NR2; • R2 is a hydrogen atom or a linear or branched C 1 -C 4 alkyl radical, a benzyl radical or an acetyl radical; • R1 is a saturated, linear or branched C 1 -C 10 alkyl radical, which is substituted with or interrupted by a cationic radical, optionally interrupted by one or more oxygen atoms and/or by one or more groups NR2, optionally substituted with one or more radicals chosen from hydroxyl, alkoxy or C 1 -C 4 hydroxyalkyl radicals; or • R1 is a saturated, unsaturated or aromatic cationic 5- to 8-membered heterocycle optionally substituted with one or more radicals chosen from C 1 -C 4 alkyl, hydroxyl, C 1 -C 4 alkoxy, amino, (C 1 -C 4)alkylamino, di(C 1 -C 4)alkylamino, thio, (C 1 -C 4)alkylthio, carboxyl, (C 1 -C 4)alkylcarbonyl, sulfonyl, amido or C 1 -C 4 hydroxyalkyl radicals; and when Z1 represents NR2 then ▪ R1 and R2 may form, together with the nitrogen atom to which they are attached, a saturated or unsaturated cationic 5- to 8-membered heterocycle optionally substituted with one or more radicals chosen from C 1 -C 10 alkyl radicals and hydroxyl, C 1 -C 4 alkoxy, amino, (C 1 -C 4)alkylamino, di(C 1 -C 4)alkylamino, thio, (C 1 -C 4)alkylthio, carboxyl, (C 1 -C 4)alkylcarbonyl, sulfonyl, amido and C 1 -C 4 hydroxyalkyl radicals, it being possible for this heterocycle to contain one or more heteroatoms chosen from N or O, preferably N; or ▪ R1 and R2 may form, together with the nitrogen atom to which they are attached, a saturated or unsaturated noncationic 5- to 8-membered heterocycle substituted with a cationic radical and optionally substituted with one or more radicals chosen from C 1 -C 10 alkyl radicals and hydroxyl, C 1 -C 4 alkoxy, amino, (C 1 -C 4)alkylamino, di(C 1 -C 4)alkylamino, thio, (C 1 -C 4)alkylthio, carboxyl, (C 1 -C 4)alkylcarbonyl, sulfonyl, amido and C 1 -C 4 hydroxyalkyl radicals; ▪ R1 and R2 may form, together with the nitrogen atom to which they are attached, a saturated or unsaturated cationic 5- to 8-membered heterocycle optionally substituted with one or more radicals chosen from C 1 -C 10 alkyl radicals and hydroxyl, C 1 -C 4 alkoxy, amino, (C 1 -C 4)alkylamino, di(C 1 -C 4)alkylamino, thio, (C 1 -C 4)alkylthio, carboxyl, (C 1 -C 4)alkylcarbonyl, sulfonyl, amido and C 1 -C 4 hydroxyalkyl radicals, it being possible for this heterocycle to contain one or more heteroatoms chosen from N or O, preferably N; or ▪ R1 and R2 may form, together with the nitrogen atom to which they are attached, a saturated or unsaturated noncationic 5- to 8-membered heterocycle substituted with a cationic radical and optionally substituted with one or more radicals chosen from C 1 -C 10 alkyl radicals and hydroxyl, C 1 -C 4 alkoxy, amino, (C 1 -C 4)alkylamino, di(C 1 -C 4)alkylamino, thio, (C 1 -C 4)alkylthio, carboxyl, (C 1 -C 4)alkylcarbonyl, sulfonyl, amido and C 1 -C 4 hydroxyalkyl radicals; • An - represents an anion or a mixture of anions which are organic or inorganic and are cosmetically acceptable,