Correlative light-electron microscopy (CLEM) aims at a better understanding of cell mechanisms by relating dynamics with structure. However, LM and EM images are of very different size, resolution, field-of-view, appearance, usually requiring manual assistance at one or several stages. We have defined an original automated CLEM retracing-and-registration method involving a common representation with adaptive scale for both types of images, and the specification of appropriate descriptors and similarity criterion for the EM patch search.