This latest incident follows the deaths of 12 people earlier this month when their boat capsized in the Channel on its way to Britain and highlights the pressure on the British and French governments to find ways to tackle the boat crossings.
Jacques Billant, the Prefect of the Pas-de-Calais region, said rescue crews were alerted that a boat with 59 people onboard was in difficulty in waters off the coast of Ambleteuse in the Pas-de-Calais area.
"A new drama took place around one in the morning and we deplore the death of eight people," he told a news conference on Sunday, adding that the other 51 onboard were now in the care of rescue and medical crews.
The dead were men from Eritrea, Sudan, Syria, Egypt, Iran and Afghanistan, he said.
The Channel is one of the world's busiest shipping lanes and currents are strong, which makes crossing on small boats dangerous.
The latest incident brings to 46 the number of people who have died trying to cross the Channel from France since the start of the year, Billant said.
On September 14 alone there were eight attempts to cross the Channel from France and some 200 migrants were rescued, he said.
9°C