The French industrialist Vincent Bolloré in effect seized control of Havas yesterday, winning four seats on the board for himself and his investment vehicle, and plunging the advertising group into renewed uncertainty.

His sweeping victory at a rowdy annual meeting could trigger the departure of Alain de Pouzilhac, the chief executive who fought tooth and nail to keep Mr Bolloré off the board and accused him of being an untrustworthy corporate raider planning a takeover by stealth.

But his triumphant opponent, surrounded by scores of cameras and a handful of delighted supporters, said he had no wish to see Mr de Pouzilhac leave - immediately adding that there were plenty of people in Paris to replace him if he chose to quit.

The chief executive, who has been with Havas for 30 years and had been aggressively confident throughout the five-hour meeting, told shareholders that he would take the personal consequences but later insisted that he would not resign.

This added to doubts about Havas's future as the world's fifth-largest advertising group, with investors either fearing or hoping for its break-up under Mr Bolloré, its biggest shareholder with a 20% stake, or its eventual sale to one of its much bigger rivals.

Catcalls, jeers and whoops of joy accompanied the sparring match between the two. With a mixture of Gallic charm and savagery, they took to the stage with roving mics to land a series of painful blows on each other in front of a thousand shareholders in two overfilled halls.

Mr Bolloré declared "I am not a wolf any more than I'm Darth Vader."

"Be reasonable" and "let's look at things squarely in the face," he repeatedly said as some shareholders booed his remarks that he was a long-term investor in "a magnificent firm, rich in talent" and whose recovery he had helped by putting in €350m (£235m) in total.

He conspicuously failed to map out an alternative strategy for Havas - claiming that he needed the inside financial information available to the board to do so - but he accused the incumbent board of making risky overseas investments that had caused the stock to collapse.

He accused Mr de Pouzilhac and his external advisers of running a systematic campaign of denigration about him for eight months. "This situation simply can not go on and the only ones interested in it continuing are the competitors of Havas," he said to derisive whistles and loud cheers.

Turning to his opponent, he said: "Unlike you, I don't see this as about all or nothing." He added that even his request for four seats on the board would have been negotiable if Mr de Pouzilhac had agreed to discuss it.

The chief executive, putting venom into his blows, retorted that Mr Bolloré was mounting personal attacks on him and accused him of consorting with competitors.

"These rivals are using you to destabilise us and a little word from you would have stopped this - and we have been waiting for it for months. All you had to say was: 'It's not true.' " he said.

He told Mr Bolloré to his face that he didn't even understand the business he had invested in because he had praised TF1, France's biggest TV channel, as a Havas client. "You're very badly informed; Canal+ is our TV channel."

But Mr de Pouzilhac's presentation of Havas's glowing prospects as an innovative business, more responsive than its rivals to changes in client and consumer demands and in media technology, fell on deaf ears. As did the promise of a faster recovery in the second half of this year.

In a series of devastating votes, more than 70% of shareholders turned out to spurn Mr de Pouzilhac's appeals to back the board and voted in the Bolloré slate, giving the raider himself almost 60% of the vote. The board secured four of its own nominees, including an 87% vote to re-elect Havas's creative director, Jacques Séguéla, but lost the chairman of its remuneration and nominations committee - and several resolutions on stock options for directors and staff.

Mr Bolloré hailed the result as a triumph for shareholder democracy - and for getting proportionate representation on the board.

He pledged to set out his strategy in the "silence" of the board - an ominous warning for the 14 new colleagues on the other side.