As French media company Vivendi continues its tussle with Italy’s Mediaset, 41% of which is owned by Silvio Berlusconi, police have raided its Paris headquarters and seized unidentified documents.

The raid was connected with an investigation into alleged market manipulation related to Vivendi’s purchase of a stake in Mediaset last year.

Vivendi’s portfolio includes production giant Canal Plus. Mediaset remains a major TV power in Italy, a key part of the southern European territory where Vivendi wants to expand.

Business mogul Vincent Bolloré controls Vivendi, which he is aiming to transform into a more balanced company with more digital and gaming assets balancing out pay-TV and film, which face increasing revenue pressure. His battle with Berlusconi could determine the future of both companies, European analysts say.

After Mediaset filed a criminal complaint in Milan, prosecutors began looking into Vivendi’s acquisition of nearly $2 billion in Mediaset shares in the open market, about a 30% stake in the company.

Fininvest, Berlusconi’s holding company, has accused Vivendi of undermining investor confidence and then swooping in to buy large blocks of shares, effectively executing a hostile takeover.

A Vivendi spokesman confirmed the raid to the Wall Street Journal but said the company “acquired its stake in Mediaset totally legally and transparently.”