The European Commission this week launched an in-depth investigation into a provision in the Belgian tax regime that gives major tax breaks to multinational corporations.

It was not the tax regime in Belgium but Luxembourg that caused an uproar this fall, with critics crying foul over sweetheart tax deals for major corporates in what become known as the LuxLeaks scandal. The International Consortium of Investigative Journalists examined thousands of leaked documents that detailed advanced tax agreements for hundreds of large corporations negotiated by PwC with Luxembourg. It also led to a political firestorm for newly installed European Commission President Jean-Claude Juncker, who served as Luxembourg’s prime minister when many of the deals occurred.