At least six people were injured, who were taken to the Port-Bouet camp in Abidjan for treatment, the spokesman for French forces in Ivory Coast said.
Student Ange Koutaye Ismael, 19, said he saw four bodies carried out of the plane, which had been broken in two in the shallow waters.
He said he was at home when he noticed a plane flying low over his neighbourhood. When he heard a plane had crashed on the beach, he ran down to film it.
Stormy weather probably played a role in the crash, he said.
"There was winds yesterday and I saw how planes seemed to have difficulties in getting up," he said.
Air traffic at the airport appeared to continue after the crash, according to flight-tracking website FlightRadar24.
In February 2000, a Kenya Airways Airbus 310 carrying 179 people destined for Lagos, Nigeria crashed into the ocean after take-off from Abidjan, leaving only 10 survivors.
At least four people are believed to have been killed when a cargo plane crashed into the Atlantic Ocean just after taking off from Ivory Coast's airport in Abidjan.
Witnesses said they saw at least four bodies as hundreds of onlookers gathered at the beach and rescue workers ran to the scene.
Security guards at the scene said the plane was carrying material for the French army.
The plane wreckage was scattered in the shallow waters.
It is reported that a plane has crashed into the sea this morning off Ivory Coast.
The plane is believed to have taken off from the international airport in Abidjan but crashed shortly afterwards.
According to the reports, witnesses saw the bodies of two people pulled from the wreckage with another two still visible.
The plane, believed to be a cargo plane carrying freight for the French army, is reported to have crashed during a lightning storm and heavy rain.
More to follow.