French bank Societe Generale has been drawn into the corruption case against the son of Equatorial Guinea's president, a judicial source said on Monday.
Teodoro Obiang Nguema, one of the country's vice-presidents, was charged by French prosecutors in March 2014 with money laundering and misappropriation of public funds.
French authorities have already seized the Obiang family's six-storey mansion on the chic Avenue Foch in Paris as well as several luxury cars.
They also took away vanloads of possessions including paintings by famous artists, a clock worth an estimated three million euros ($4.2 million) and wines worth thousands of euros a bottle.
Societe Generale was last week given the status of "assisted witness" in the case -- which lies between a witness and a suspect in the French legal system.
French investigators say the bank's local subsidiary, Societe Generale Bank in Equatorial Guinea, has played a "major role" in the alleged channelling of funds to Obiang.
The 46-year-old's father, who shares the same name, has ruled Equatorial Guinea with an iron fist since 1979.
Societe Generale confirmed it had been given the status of "assisted witness" in the case and said it would "naturally cooperate with the judiciary".
The younger Obiang has also been pursued by US authorities, who have accused him of racking up more than $300 million through embezzlement, extortion, and money laundering, while earning a government salary of less than $100,000 a year.
US prosecutors forced Obiang to turn over more than $30 million in ill-gotten gains -- including a Malibu villa, a Ferrari and Michael Jackson memorabilia -- last October.
"Obiang shamelessly looted his government and shook down businesses in his country to support his lavish lifestyle, while many of his fellow citizens lived in extreme poverty," US Assistant Attorney General Leslie Caldwell said at the time.