In 1929, he signed, together with Camille Huysmans, the "Compromis des Belges" (Compromise of the Belgians). This document judged separatism, accepted the cultural autonomy of Flanders and Wallonia, and suggested a greater autonomy for municipalities and provinces.
Until his death, he would continue to work on improving the political situation of Wallonia. In 1923 he left, the "Assemblée wallonne" (the Wallonian Assembly), which he co-founded in 1912, because it had not paid enough attention the Walloon working class.