Vincent Bolloré is questioned by police near Paris over contracts to run ports in Guinea and Togo.Read more
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.
Togo was the only African state to vote against a UN General Assembly resolution effectively calling on the US to withdraw its recognition of Jerusalem as the capital of Israel.
Many African states - including South Africa, Nigeria and Ethiopia - voted for the resolution, while others - such as Uganda, Rwanda and South Sudan - abstained.
On Wednesday, Mr Trump warned he might cut financial aid to states who voted in favour of the resolution while the US ambassador to the UN, Nikki Haley, said the US would be "taking names" and "watching carefully" how countries voted.
Botswana - a staunch US ally - dismissed the threat, saying it would not be "intimidated" as it voted in favour of the resolution.
Togo was one of only nine states to vote against it. The others were Israel, Guatemala, Honduras, the Marshall Islands, Micronesia, Nauru, Palau and the US.
Togolese footballer Francis Kone won an award after his quick thinking on the pitch saved an opponent's life.
Tens of thousands of opposition supporters in Togo have marched in the capital, Lome in what they call the next phase of their campaign to force out President Faure Gnassingbe.
There were also big numbers of protesters in the second largest city of Sokode and the northern town of Bafilo, where youths blockaded a major highway connecting the north and south of the country.
Organisers had billed today's march as a "final warning" to the regime.
More rallies are expected on Thursday, described by organisers as a "march of anger", AFP news agency reports.
The main opposition leader, Jean-Pierre Fabre, said that they were going to maintain pressure on the government.
Protesters carried placards demanding the restoration of the 1992 constitution, which limited the number of presidential terms to two. Mr Gnassingbe is serving his third term in office.
He succeeded his father, meaning the same family has ruled Togo for 50 years.
At least four people have been killed and hundreds injured during weeks of anti-government protests in Togo.