The invention relates to a one step aqueous synthetic process, based on inorganic polymerisation of molecular precursor, in order to access to  functionalized  nanoparticles (2 to 50 nm) of at least one metal derivative such as TiO₂, ZnO or CeO₂, and at least one type of carboxylic and/or sulfonic acid derivative organic compound chemically bound in a covalent manner.