The Defense Ministry in Paris said 300 more French troops joined the U.N. peacekeeping force of 7,500 Saturday night and took the airport, CNN reported.
U.N. helicopters patrolled Abidjan's skies Sunday morning as the streets were nearly deserted, a resident told CNN.
A journalist in the city said many residents were afraid to leave their homes, but were being forced to venture out to get water.
U.N. Secretary-General Ban Ki-moon Sunday pressed Allasane Ouattara, the U.N.-recognized winner of last year's election, to investigate a massacre in the western town of Duekoue, the BBC reported.
Ouattara denied his forces were responsible but said he had ordered an investigation and would welcome an international inquiry, U.N. spokesman Martin Nesirky said.
The Duekoue massacre occurred between Monday and Wednesday as Ouattara's forces marched on Abidjan, said Guillaume Ngefa, the deputy human rights director at the U.N. mission.
He blamed 220 deaths on Ouattara's forces and 100 on the retreating army of former President Laurent Gbagbo, who refuses to step down. Some reports have a death toll as high as 1,000.
Abidjan, a city of 5 million, came under siege Thursday.
Henry Gray of the Doctors Without Borders charity said one city hospital alone treated 50 people Friday for gunshot wounds, The Sunday Telegraph reported.
Ouattara's forces maintained a barrage on Gbagbo's residence and presidential compound Sunday, the report said.
U.S. Secretary of State Hillary Clinton and British Foreign Secretary William Hague again Sunday called for Gbagbo to quit immediately.
Clinton also said Ouattara's forces must "respect the rules of war and stop attacks on civilians."