Two security agents and two migrants were killed in a shooting in Loon-Plage near the northern city of Dunkirk, French media reported on Saturday, citing security sources.
A 22-year-old man turned himself in to nearby authorities following the shooting, saying he had been the attacker and had also killed a fifth person in a nearby town earlier that day, according to French media.
Authorities found three more weapons in the man's car, French media reported.
Representatives for the Interior Ministry and the Justice Ministry did not immediately respond to requests for comment. It was not immediately clear what the motives were for the shooting.
Loon-Plage, located about 10 kilometres from the English Channel, is the site of a migrant camp.

At least 14 killed in explosion at weapons depot in Syria
US hits five Iranian oil tankers after attack on Navy ships
UK flights resume after major air traffic outage but airports warn of more disruption
Serbia's President Vucic dissolves parliament, calls snap elections
With large crowds attending, Norway lays King Harald to rest
Jordan intercepts 18 Iranian ballistic missiles
Air traffic control issue disrupts flights at major UK airports
At least 73 injured after Houthi rebels attack Saudi civilian and energy facilities
