Belgian historical research concerning the repression of collaboration after the Second World War, has mostly overlooked the East Cantons. This mostly German-speaking region only became a part of Belgium in 1920, as a consequence of the treaty of Versailles. The integration of these populations turned out to be a very complicated process. In 1940, Nazi-Germany did not only occupy the East Cantons like the rest of Belgium, but annexed them back into the Third Reich. One of the main conclusions of the regional historiography is to view the repression of the collaboration as another step in the general misunderstanding between the local inhabitants and Belgian State authorities. This is evidenced by the high conviction rate (2.41% of the local population) and by assimilationist discourses which accompanied the workings of the Belgian military courts. In this contribution, we study the role of judicial actors in the actual establishment of the repression of collaboration and the civic purge in a top-down and a bottom-up approach. We analyse the special prosecution policy developed by the military prosecution office during the post-war period for with the enemy. We also show how political and administrative actors reinforced the living sentiments of injustice among the local population.