French financier Vincent Bolloré has written to media buying group Aegis to demand a meeting of shareholders.

Mr Bolloré, who owns a 29% stake in Aegis, confirmed the long-expected move today, which marks his second attempt to gain seats on the company's board.

Aegis is obliged to call the meeting but can take up to three weeks before doing so. The meeting would then take place up to four weeks later, making it unlikely it will be convened before late November.

Aegis headed off a previous challenge from Mr Bolloré at its annual general meeting in June, when a majority of shareholders voted against his campaign for two seats on the board.

The company asked investors to reject his move because it felt his role as chairman and shareholder of rival advertising group Havas created a conflict of interest

However, Mr Bolloré believes he deserves seats on the board to reflect the level of his stake in Aegis, which owns the Carat and Vizeum networks.

As a shareholder with more than 10% of the company, he is entitled to ask for an extraordinary general meeting.

The stage is now set for a battle for investors' hearts and minds, with the Aegis chief executive, Robert Lerwill, under pressure to secure their backing in the latest round of his struggle with Mr Bolloré.

Relations between the two camps are cool, after the Frenchman snubbed executives by failing to sit down to a one-on-one briefing to discuss Aegis's most recent financial results.

Many analysts believe Mr Bolloré's efforts to get seats on the Aegis board represent an opening gambit in a push to acquire the company.

The financier cannot add significantly to his stake - acquired since August last year - without crossing the 30% threshold at which he would be obliged under City rules to make a takeover bid.

WPP's Sir Martin Sorrell, who backed away from bidding for Aegis last year, will also be keeping a close eye on the situation.

Earlier this year, Sir Martin - who has always been interested in acquiring Aegis's market research division Synovate - said he thought Mr Bolloré was aiming at full ownership.

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