French interior minister Gérard Collomb has called for an addendum to the Le Touquet agreement with Britain about the handling of migrants in Calais, reports RFI.
President Emmanuel Macron is expected to raise the question with UK prime minister Theresa May when he meets her on Thursday.
Collomb and Macron are to visit Calais two days before the president's British trip as France steps up pressure for Britain to share more of the costs of managing the migrants who flock to the port in the hope of crossing the Channel.
The 2004 agreement put the British border at Calais, allowing its customs and police to operate there.
Before the UK's Brexit vote, Macron, at the time economy minister in a Socialist government, said the agreement would have to be renegotiated if the leave vote won.
His government is not going that far today, with Collomb simply calling for a new clause to be added that should ensure that Britain would "take on a certain amount of the costs" and accept more refugees, especially unaccompanied minors.
A French presidential statement a week ago said that "ways to improve the handling of migrants on the common border in Calais" would be discussed at the bilateral meeting at the British military academy in Sandhurst, south of London.
The British statement on the meeting did not even mention the question, however, simply saying that defence and security would be discussed.
They argue that they have repeatedly financed the construction of increasingly imposing barriers to prevent migrants approaching the entrance to the Channel tunnel.