There are around 1,300 immigrants in the northern French port of Calais at the moment.
Most of them are Eritreans, Somalians or Syrians and they are all seeking asylum in Great Britain.
Calais mayor Natacha Bouchart claimed on Tuesday that British immigration policy means immigrants "consider it an Eldorado" and reproached London for demanding tighter security at the Calais port but was not contributing enough to the cost, which she put at 10 millions euros a year.
Recognising that blocking the port “would be illegal”, Bouchart declared she wanted “to make a strong gesture towards the British”, after meeting French Interior Minister Bernard Cazeneuve and asking him “to have tough negociations" with United Kingdom.
Cazeneuve, who was in London last Friday, had called on the British to help financially with security at the port, according to a ministerial source.
Bouchart and Cazeneuve agreed on opening a day centre for immigrants in Calais.
Most centres built to help immigrants have rapidly become overcrowded and have closed.