It comes less than two weeks after 12 people, including six children and a pregnant woman, died when a boat carrying dozens of migrants sank in what was the deadliest loss of life in the Channel this year.
The French coast guard said the boat was seen heading towards a beach in the town of Ambleteuse but rescue teams could not offer assistance from the sea.
On the beach, emergency services provided care to 53 people and confirmed eight had died, the coast guard said. No other people were found during sea searches.
An investigation has been opened by the Boulogne-sur-mer public prosecutor's office.
A UK government spokesperson confirmed the latest incident and said French authorities were leading the response and investigation.
Foreign Secretary David Lammy said it was "awful" to hear of a "further loss of life" in the Channel.
He told the Sunday with Laura Kuenssberg programme that many people were "of course not able to make it" across the Channel, having seen the types of rubber dinghies people have been using.
He also reiterated the government's plan to work with European partners to tackle the criminal people-smuggling gangs to deter small boat crossings.
Regional prefect Jacques Billant is holding a news conference in the town of Ambleteuse.
There has been a spate of crossing attempts across the Channel in the last two days with the arrival of calmer weather.
French maritime authorities said that 200 people were rescued in a 24-hour period over Friday and Saturday.
The French coast guard and other first responders rescued people onboard four separate boats - one with 61, another with 55, and two others with 48 and 36 each.
Eighteen attempted crossings were monitored by authorities over the course of the day.
Including the eight latest victims, a total of 45 people have died in the Channel this year - the highest reported number since 2021, according to the UN's International Organisation for Migration.
