The invention relates to the field of preparing aqueous dispersions of organic, organometallic or inorganic particles. In particular, the invention relates to the preparation of aqueous suspensions comprising organic, organometallic or inorganic particles and at least one particular copolymer obtained by polymerization of at least one acid and at least one compound or at least one ester derived from a particular acid, in the presence of water, at least one initiator compound and at least one activator compound, followed by total or partial neutralization by means of at least one compound chosen from alkali metal hydroxides, alkaline earth metal hydroxides, alkaline earth metal dihydroxides and mixtures thereof. The invention relates to such a particular copolymer having a low polydispersity index and weight-average molecular weight, the preparation process thereof and the use thereof, especially for the preparation of an aqueous paint composition.