Five people, including a seven-year-old girl, have died while trying to cross the English Channel in the early hours of Tuesday, French officials have said.
They said the victims were trying to get to the UK on an overloaded boat carrying 112 migrants.
Authorities said the boat ran aground on a sandbank after leaving Wimereux, near Boulogne, before continuing on.
One local volunteer told reporters that the deceased child’s father had seen “his little girl die before his eyes”.
Dany Patoux, a volunteer with the Boulogne-based migrant charity Osmose 62, told French radio network Franceinfo the child was a young girl who he “knew well”.
Ms Patoux added that she had seen the father of the child crying after the tragedy, noting that he “fell into our arms” once he reached the shore.
Several search-and-rescue operations are under way to find other survivors who may have fallen into the water, officials said.
The prefect of Pas-de-Calais, where Wimereux is located, said the boat set sail from the Plage des Allemands with “an unprecedented 112 people on board”.
The “heavily laden boat” then “appeared to be in difficulty a few hundred metres from the beach after passing a sandbank”, the French maritime prefecture said in a statement. “Its engine stopped and two people fell into the water near the boat.”
Upon seeing the boat in distress, prefect Jacques Billant said the Abeille Normandie patrol boat was immediately deployed to rescue those who had set off on the boat. When they arrived, several people were “unconscious and in great difficulty”.
Six people were taken aboard the patrol boat, before being taken to the beach to be treated by emergency services.
Another 47 people were rescued from the boat by French authorities, according to Mr Billant, but a further 57 remained on board as they did not wish to be rescued.
The UK’s Border Force said it had brought about 70 migrants to shore on Tuesday. It added that more people were on board a vessel heading for Dover.