Drahi, who controls 77.8% of the votes in Altice, offered on Sept. 11 to buy all the shares in the group he does not already own at 4.11 euros each, then a premium of 23.8% to its Sept. 10 closing price.

Shares in the company closed at 4.46 euros on Monday.

In a statement, shareholder Sessa Capital said it and others which together hold Altice shares worth 103 million euros, would seek to block the deal in its current form.

Sessa CEO John Petry called the deal called "unfair", and said the company's board had not adequately represented shareholders' interests.

"It looks even worse when viewed in the context of the subsequent global equity rally and the highly positive vaccine development results," he said in a statement.

Altice said it had received a copy of a second complaint from Lucerne Capital, which holds a stake worth 94 million euros, calling for an inquiry into the company's corporate governance.

A hearing is set for Dec. 23, before shareholders meet to discuss the offer on Jan. 7.

The buyout "is in the interests of Altice Europe and its stakeholders, and part of a proper decision-making process," the company said, adding it was "confident" it would win complaints against it.

Although Altice is France's second-largest mobile provider, it is based in the Netherlands and has its primary share listing on Euronext in Amsterdam.

A spokesman for European shareholders' rights group VEB told Reuters it supported the complaints against the company.

(Reporting by Toby Sterling; Editing by Jan Harvey)