Résumé : A chemical effect affecting the shape of the copper, manganese and oxygen Auger lines provides a very useful tool for characterization of the oxides formed during high temperature and low pressure oxidation of dilute Cu-Mn alloys. The state of oxidation of these elements changes the electron distribution in the valence bands, and the relative amplitudes of the Auger transitions involving one or two valence levels have been used as a measure of this effect.