The 30-mile stretch of coast being used by migrants is too large to patrol and resources are limited, says mayor of Teteghem in northern France.
The French authorities have set out plans to improve cooperation with UK and increase their coastal surveillance.
British and French sea rescue services intervened in the early hours on Christmas Day to bring to safety at least 40 migrants, including children, attempting to cross the English Channel to England in precarious conditions in five separate boats.
Italy's far-right interior minister Matteo Salvini said he has demanded an explanation from Paris over an alleged incursion into his country by a French police van which Italian media said was captured on CCTV releasing two men thought to be African migrants in woods near Turin.
The migrant issue has become a decisive test for all those on the Left who campaign for the emancipation of the people and equal rights for all. Mediapart publishing editor Edwy Plenel argues that far from protecting existing rights, any concession to the politics of rejection, to the favouring of one nationality over others or to policies based on borders and identity, will simply help the cause of the extreme right.
Italian Deputy Prime Minister Matteo Salvini has called on France to stop turning back migrants who succeed in crossing into the country from Italy at the Rivierra town of Ventimiglia, adding that French President Emmanuel Macron 'is the first who should show solidarity and sensibility by reopening the border'.
The youth arms of France's Rassemblement national (National Rally) party, formerly called the Front National, and its far-right Italian ally, the League, staged a joint demonstration near the French-Italian border on Sunday to demand tough measures against what they said was the 'overwhelming' of Europe by migrants.
Migrant girls, mostly from sub-Saharan Africa, attempting to cross into France from Italy are being exploited by would-be smugglers offering to drive them across the on the countries' common Riviera border in exchange for sex acts, says a report by the Italian branch of the charity Save the Children.
Late in June, after days of diplomatic wrangling, 234 migrants rescued off the Libyan coast while attempting to reach Europe in flimsy dinghies were finally allowed to disembark in Malta after several countries agreed to receive quotas from the group. Earlier this month, 51 of them arrived in France. Mediapart travelled to Toulouse, where some were given provisional accommodation, to listen to the harrowing stories of their experiences in Libya, where black Africans are subject to endemic racism and many become the prey and prisoner of vicious local militias. “If an Arab catches you, he sells you,” said one of the survivors. “When you are black, you are a commodity, you’re bought and sold on.” Mathilde Mathieu reports.
Moments after ruling by Constitutional Council backing olive farmer Cédric Herrou, the hashtag #fraternité started trending on Twitter.
French president Emmanuel Macron said France would take a 'few dozen of the migrants as he criticised the German NGO running the ship.
On eve of EU migration policy summit, French president says he favours financial penalties on EU states that refuse to accept migrants.
A report published by NGO Oxfam says its interviews with migrant children trying to cross from Italy to France on the Riviera border found complaints of being 'physically and verbally abused, and detained overnight in cells without food, water or blankets and with no access to an official guardian', and also claims that some children had the soles of their shoes cut off before being sent back to Italy.
French President Emmanuel Macron and Italian Prime Minister Giuseppe Conte, meeting in Paris on Friday after a week-long dispute over Italy's decision to refuse the disembarkation of migrants rescued at sea by NGO ship Aquarius, agreed that the EU should set up migration processing centres in African countries of departure.