MediaCom had handled Universal for 32 years and it is thought that UK executives at the world’s biggest music company had been happy with their relationship with the WPP agency.
However, Bolloré is understood to have pushed for the business to move to Arena’s parent, Havas, after becoming chairman of Vivendi, which owns Universal, in 2014.
Arena will handle traditional media, while Universal looks after digital in-house. Havas had already won Universal’s media business in other markets around the world.
Bolloré has also fuelled speculation that he could merge Vivendi and Havas, which were part of the same group before 2000. "It is clear that something will happen," Bolloré said last month.