French President Jacques Chirac has warned that Africans "will flood the world" unless more is done to develop the continent's economy.
Thousands of Africans are risking their lives to reach Europe
In a TV interview, Mr Chirac said nearly 50% of Africa's 950m population was under 17 and that by 2050 there would be two billion Africans.
He said the necessary resources had to be made available to help Africa.
"We have an immense problem [in Africa] ... which is that of development," he said in the Bastille Day interview.
'Back to basics'
"If we do not develop... Africa... if we do not make available the necessary resources to bring about this development, these people will flood the world," he said.
Mr Chirac stressed the need to "go back to the basic issues with regard to immigration".
"One cannot solve a problem entirely outside its context, and the context here is north-south [divide]," he said.
Earlier this week, French Interior Minister Nicolas Sarkozy said Europe had to be careful not to turn itself into a fortress just to keep out immigrants.
Addressing a European-African migration conference in Morocco, Mr Sarkozy said the so-called zero immigration concept was a dangerous myth.
Search for solutions
Delegates at the conference were trying to develop a common approach between Europe and Africa.
Proposals included tougher policing and action against human trafficking but also measures to deal with the poverty and conflict which drive would-be migrants to seek a better life elsewhere.
Last month, Spain announced a three-year diplomatic drive in West Africa to try to halt the flow of African migrants to Europe.
Nearly 8,000 Africans aiming to enter the EU have arrived in Spain's Canary Islands alone in 2006.
About 1,000 more are believed to have died attempting dangerous voyages in the Atlantic to reach the Canary Islands.