Calais mayor Natacha Bouchart has threatened to shut the French port unless Britain helps address the problem of immigrants arriving there to illegally cross the English Channel. Bouchard has demanded financial help.
Bouchart said she was prepared to close the port if Britain did not help reduce the number of immigrants attempting to cross the English Channel.
The mayor, who met French Interior Minister Bernard Cazeneuve in Paris on Tuesday, said she wanted Britain to revise its immigration policy, and help Calais address the problem.
"This is taking my city and the population hostage," said Bouchart after the meeting. "I have the means to pressure... I could make the decision to block the port."
With some 1,300 immigrants in the northern French port, Bouchart claimed that the presence of those seeking a new life in Britain - where residency is seen as easier to obtain - was draining local government finances.
Bouchard condemned London for demanding that security be boosted at Calais without helping to finance the extra cost, claiming that it would amount to some 10 million euros ($13 million) a year.
The mayor said she had discussed the possibility of blocking the port, admitting that she knew she would not be able to sanction it.
"It would be illegal," she said, "but today I want to make a strong gesture towards the British."
Many of the migrants are believed to be Eritrean, Sudanese or Somali, large numbers of whom arrive in Europe by boat. Some attempt to cross the Channel by hiding on board ferries and freight trains.