Royal and Development Minister Annick Girardin represented France at the pan-African New York Africa Forum in Libreville, Gabon, 29-30 August.
As well as pushing for African cooperation ahead of the Cop21 climate change conference in Paris in December, Royal announced that the conference would take place on the 11-12 November on the Mediterranean island of Malta.
She said that two-thirds of those fleeing were doing so because of environmental reasons.
"They can't work their fields, there's nothing left to eat and no income," she commented.
The French ministers were to hold talks with Gabon's President Ali Bongo, who has referred to Europe as the main victim in the current migration crisis.
Bongo says the bloc will need to work closely together with the migrants' countries of origin to find a solution.
Also present at the forum was Côte d'Ivoire president Alassane Ouattara.
The migrant issue was not only a catastrophe but shameful, he said.
Royal and Girardin were to visit Pongara Park and were to discuss forest preservation with the authorities.
They were also set to participate in the inauguration of a centre for satellite imagery and data management dedicated to the long-term management of natural resouces in central Africa.
Girardin oversaw the signing of a 17.8-million-euro project that the government and the French agency for development (AFD) say will contribute to fighting elephant poaching and ivory trafficking in Gabon.
In an official statement prior to arriving in Libreville, Royal said she would emphasise the central role African nations can play ahead of the Cop21 summit, which starts on 30 November in Paris.
"Gabon was the first African country to publish its contribution to the Paris accord," according to the statement.
Bongo said that after the failure in Copenhagen in 2009, the Paris summit must not fail.