By Mathieu Rosemain

CANNES, France (Reuters) - Havas <HAVA.PA> Chief Executive Officer Yannick Bollore said on Thursday that there were no merger talks ongoing between his advertising company and Vivendi <VIV.PA>, the French media giant chaired by his billionaire father.

Vincent Bollore, who took the helm of Vivendi in 2014, last month evoked the possibility of a tie-up between the two companies.

The French tycoon owns about 60 percent of Havas and about 15 percent of Vivendi via his family-controlled group. He recently tightened his grip on the media company by nominating his son Yannick to the board.

"There's no official discussion between the two companies," the Havas chief executive said in an interview in Cannes.

However, the CEO of the world's sixth-largest advertising company did not rule out the possibility of building closer ties with Vivendi in the future.

"Havas and Vivendi have two things in common: first, a common shareholder; second, the fact that we evolve in similar environments, with what's going on in the digital revolution and with big data," Yannick Bollore said.

Bollore also said that there would be no change to the outlook for the advertising business if Britons voted on Thursday to leave the European Union.

(Reporting by Mathieu Rosemain; Editing by Richard Lough and Geert De Clercq)