The invention relates to nanoparticles having a core that is fully or partially formed by at least one UV-absorbing organic compound in crystallized form and coated with an outer layer formed by at least one hydrophilic polymer, said UV-absorbing organic compound(s) and hydrophilic polymer(s) being associated in a weight ratio of organic compound(s) to hydrophilic polymer(s) varying between 0.2 and 0.4.
