In situ measurements of redox potential are rather difficult to perform and provide only sparse information on its spatial distribution. To delineate redox fronts in a contaminant plume, the self-potential (SP) method can be a helpful complement to geochemical measurements. Here, we apply the SP method to the Entressen municipal waste landfill (south-eastern France) over a 20 km2 area. The results show a large negative SP-anomaly of ~-400 mV with respect to a reference station taken outside the contaminant plume. Once removed the electrokinetic component associated with groundwater flow, the residual self-potential signals are linearly correlated with in situ measurements of redox potential. We propose a quantitative relationship between self-potential and redox potential, which would be used to invert self-potential measurements in terms of in situ redox potential values in contaminant plumes.