French troops guarding the Central African Republic capital Bangui's international airport have accidentally killed two Indian citizens, the French defence ministry said.
Six others were injured in the incident on Monday, a statement said.
India PM Manmohan Singh has said efforts will be made to ensure the safety of 100 Indian nationals in CAR.
Rebels in the CAR have taken Bangui after President Francois Bozize fled.
President Francois Hollande, who has sent hundreds of troops to Bangui, said the rebel fighters must respect the people.
France doubled its military detachment at the airport to around 600 troops on Saturday in order to protect French citizens as rebels approached Bangui.
A French defence ministry statement said its soldiers shot at three vehicles approaching the airport after firing warning shots and themselves coming under fire, a statement said.
Two Indian nationals and a number of Cameroonians were wounded in the attack.
On Monday, Mr Singh received a letter from President Hollande expressing regret for the incident, reports say.
"While conveying his condolences, President Hollande assured prime minister of his firm determination to investigate the tragic event and assured that the injured were under the care of French medical teams," a statement issued by India's external affairs ministry said.
CAR, which has a population of about 4.5 million, has been hit by a series of rebellions since independence from France in 1960.