claim: The Belgian author of What is Property was a member of French Parliament. He inspired a political group founded by George Valois and Édouard Berth.
supporting_facts.key: Cercle Proudhon
supporting_facts.key: Cercle Proudhon
supporting_facts.key: Pierre-Joseph Proudhon
supporting_facts.key: Pierre-Joseph Proudhon
supporting_facts.key: What Is Property?