"The supervisory board has examined the joint request by Amber Capital and Vivendi to call an extraordinary general meeting. It considers that the legal conditions required to diverge from the corporate schedule known to all shareholders are not presently satisfied", the group said in a statement.

"It reiterated that it is the guarantor of the group's corporate interest, its independence and its integrity. Accordingly, it has a duty to preserve the group in a particularcontext where one of the shareholders requesting the meeting is a direct competitor of Lagardere Publishing", the company added, referring to Vivendi.

Amber has been embroiled in a tug-of-war with the firm's managers since 2016, as it pushes for a shake-up in its governance.

It has been joined in its efforts for a board revamp by French billionaire Vincent Bollore and the Vivendi media group he controls, which has built up a 23.5% stake in Lagardere. Amber, a 20% stakeholder, and Vivendi are asking for four board seats between them.

While rejecting their AGM request, Lagardere also said its supervisory board had "to engage in constructive and composed dialogue with the shareholders".

Bernard Arnault, who runs luxury goods group LVMH, is investing in the personal holding company of Arnaud Lagardere, the firm's managing partner - effectively backing the firm and its bosses, which have brushed off Amber in the past.

(Reporting by Benoit Van Overstraeten; Editing by David Gregorio)