* Son of shareholder Vincent Bollore takes over as CEO
* Charismatic outgoing CEO Jones to launch tech start-up
* New CEO says to continue Jones' strategy (Adds quotes, details)
By Gwénaëlle Barzic
PARIS, Jan 8 France's Havas said Yannick Bollore, the 33-year-old son of top shareholder Vincent Bollore, would take over as chief executive of the world's sixth-biggest advertising agency.
In a surprise announcement, the company also said current CEO David Jones would leave the company to become co-founder and CEO of a new technology startup company.
Yannick Bollore was appointed chairman of Havas this summer, sparking speculation how long the charismatic Jones would want to play second fiddle to the son of his firm's main shareholder.
Bollore junior - who is married to Chloe Bouygues, the niece of French real estate tycoon Martin Bouygues - has run the media business of his father's group and entered Havas in 2011, but has relatively little experience in advertising.
Jones, 47, told a teleconference his departure had nothing to do with Yannick Bollore's appointment as chairman, although he added that Vincent Bollore had made it clear to him from the start that his son would eventually take over at Havas.
"This move is about the opportunity that is there, my desire to be an entrepreneur. I want to go and try it and would regret forever not doing it," he said.
Jones has worked in the Havas group since 1998 and became CEO in March 2011. He was the only British national running a major French-listed company.
Jones said he plans to take part in the launch of a new startup "at the intersection of social media and social responsibility" and that he would give more details about the venture, when it is launched next month.
He added the reason Havas had done so well in the past years was the role of the Bollore group as its shareholder.
French billionaire Vincent Bollore owns 35.21 percent of Havas stock, Thomson Reuters data shows. Parvus Asset Management owns 8.06 percent, and a series of other investment funds also own stakes between 3.5 and 1.5 percent of capital.
Yannick Bollore said he would continue Jones' strategy and would give more details about his management priorities at a meeting with executives in New York later this month.
A Paris-based equities trader told Reuters the departure of Jones was a negative for the group.
"He was loved by clients and a real provider of new business," he said.
Jones will remain an adviser to Havas in the coming year.
Charles Bedouelle, an analyst with Exane BNP Paribas, said in a note he expected Havas shares would react negatively to Jones' departure on Thursday.
(Reporting by Geert De Clercq, Gwenaelle Barzic and Blaise Robinson; writing by Geert De Clercq; Editing by Louise Heavens, Mark Potter and David Evans)