Because they negotiated in 2012 through Nyboma & Roupha Mbuta Nganga. The combattans agreed when Nyboma & Rouph gave the example of musicians based in London still performing. Bourman Idolo being the first to have some succes, followed by Tapis Rouge and later on Djonga. But official concerts for France-based musicians were allowed yet, until 2015/16. Later on they also allowed playbacks and showcases for Kinshasa based musicians in Europe. But sometimes it would still result in a fight (the one of Fally in Bruxelles for example back in 2017 I think). It’s that they just pay some money to the combattans every event. That’s why those youngsters in Brussels were mad at Boketshu & Babin, because they paid him money, but Fally’s showcase in Brussels was still cancelled by combattans.