PARIS, April 5 (Reuters) - France's CFDT union (The French Democratic Confederation of Labour) will take part in the next wave of rolling strikes over reform of the state-run SNCF railways (France's national state-owned railway company), its leader Laurent Berger said on Thursday. Speaking on BFM TV, Berger said "the discussions are not concluded and what the government has proposed is not acceptable." The next rail strike is due to begin on April 8. Berger expressed satisfaction that the government had agreed to allow existing SNCF workers to maintain their job perks if they are transferred to new private operators when the network is opened up to competition in line with European Union rules. "It's an extremely important point," he said.