French police have taken billionaire Vincent Bolloré into custody as part of an investigation into how his company won the contracts to operate two container ports in West Africa in 2010.
His group denies any irregular activity in Africa.
Investigators are looking into why Guinea's president Alpha Condé terminated a contract with an existing operator and gave it to the Bolloré group after he was elected to office.
They are also investigating another contract which gave the group the rights to run the Lomé container port in Togo.
