Mixed nickel cerium oxides have been used for studying the enantioselective hydrogenation of methyl acetoacetate (MAA) in methyl (3)-hydroxybutyrate (MHB). X-ray photoelectron spectroscopy (XPS) and infrared spectroscopy (FTIR) provide interesting information about the adsorption of both the reagent and the modifying agent (viz : tartaric acid). From the XPS results, we can assume that the presence of Ce3+ species, the amount of which is depending on the Nickel extent, stabilises a complex tartarate salt. The whole information lead to a new model with a stable six-membered cycle, in which the methylenic group of the reagent is involved.