A widespread rescue operation is searching for other passengers.
A sailboat sounded the alarm after spotting the ship – which was traveling in gusts of up to 18 mph – in trouble near Dunkirk.
Customs and navy patrol boats from France and Belgium visited the area, along with a lifeboat and a fishing boat.
Eighteen people were taken to hospitals in Calais and Dunkirk, according to the maritime prefecture of the Channel and the North Sea.
It is believed that people on the boat were trying to get to the UK.
The Dunkirk prosecutor’s office is investigating the causes of the shipwreck.