Bollore, who holds over 20% of Havas, has been building his stake for close to a year, but has refused to make clear his intentions towards the company, much to the annoyance of Havas chief executive Alain de Pouzilhac.
Today, he asked for four seats on the Havas board adding further weight to speculation that he will make a bid to take control of the advertising holding company, which owns Euro RSCG Worldwide and MPG. Board directors will be elected at Havas' annual general meeting in June.
Sorrell last year revealed that he had discussed the future of Havas with Bollore after the Frenchman increased his stake in Havas last September.
Today, Sorrell has gone further and, in an interview with French newspaper Le Monde, he has revealed that he and Bollore have regular discussions.
"Yes, we regularly have discussions together. Our two groups have had a relationship for two years," Sorrell told Le Monde.
However, when pressed to talk about the future of Havas, Sorrell refused to comment.
"I will not say anything on the future of Havas. Ask Alain de Pouzilhac and Mr Bollore," he said.
Relations between Sorrell and De Pouzilhac looked to have improved recently after the Frenchman had attacked the WPP chief in the press several times.
Earlier this month, the two groups did a deal to launch a new European-focused media buying agency, which the two are believed to be using in an effort to win the £76m PSA Peugeot Citroen media account. The agency, named 2MV, is 51% owned by Havas' Media Planning Group and 49% owned by WPP's Group M.
The initial disclosure last year that Sorrell and Bollore were talking led to speculation that WPP could be in the market to buy Havas, which has long been seen as a takeover target.
WPP this morning said that revenues for the first quarter of the year are up by 16% to £1.11bn, after its acquisition of Grey Global Group on March 7. In like-for-like terms, revenues rose 6% for the first quarter of the year, boosted by a 40% rise in the US to £443.9m.
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