France is seeking an emergency meeting of the U.N. Security Council to discuss the alleged sale of African migrants as slaves.
President Emmanuel Macron called the video footage aired last week by U.S. news network CNN "scandalous" and "unacceptable."
"It is a crime against humanity," Macron said after meeting with African Union chief Alpha Conde. "I hope we can go much further in the fight against traffickers who commit such crimes, and cooperate with all the countries in the network to dismantle these networks."
CNN aired footage of an apparent auction where black men were presented to buyers as potential farmhands and sold off for as little as $400. The video sparked international outrage, with protests erupting across Europe and Africa.
The UNSC meeting will likely be next week, a French diplomat said.
On Monday, U.N. Secretary-General Antonio Guterres said he was horrified and that the auctions should be investigated as possible crimes against humanity.
Criticism of EU
Human rights groups have criticized the European Union for pressuring Libya into stopping the flow of migrants to Europe.
Conde also put the blame on the European Union, accusing it of encouraging the Libyans to keep migrants in the North African country despite there being no single, universally recognized government.
"What happened in Libya is shocking, scandalous, but we must establish the responsibilities," Conde said. "In Libya, there is no government, so the European Union can not choose a developing country and ask that country to detain refugees ... when it doesn't have the means to do so."
Human rights groups have said the increased vigilance by Libyan maritime forces has forced the migrant smugglers to look for ways to unload their human cargo that can't be transported to Europe.