Around 70 people were trying to get into a small boat attempting to launch from a beach when it overturned in the early hours of Sunday morning, French media reports said.
Dozens were pulled from the water during overnight rescue efforts in Wimereux, to the south of Calais.
One person who is in a critical condition has been transferred to a hospital in nearby Boulogne-sur-Mer, a spokesperson from the French maritime prefecture told the BBC.
It said 32 people had been rescued and that one person has non-life threatening injuries.
Cause Rwanda… somehow