Around 200 French soldiers crossed the border from Cameroon to a triumphant welcome from thousands of Central Africans shouting "Thank you!" and "Save us!". They complete the 1,200-strong deployment to the former French colony.
As the nightly curfew was lifted early , Bangui's residents began venturing out onto streets that had been deserted since an explosion of violence two days earlier.
At least 300 people were killed in Thursday's massacre and subsequent reprisals, the Red Cross has said, many of them clubbed or hacked to death.
"It is reassuring to see the French," said Bangui petrol seller Adolphe.
"We are waiting for the liberation of Central Africans."
French troops, some of them on foot, patrolled the capital in a visible show of strength. Early , a French armoured vehicle took a symbolic swing past the front of the presidential palace.
A fighter jet flew low over the city, where bodies still lay abandoned outside the parliament building.
Red Cross staff continue to pick up dead and mutilated bodies from the streets, but have been overwhelmed by the scale of the task.
However, the situation appeared to have improved since . Residents contacted by telephone said only sporadic gunfire were heard overnight , in stark contrast to the intense violence of the two previous nights.
An order by President Michel Djotodia for all armed groups except international forces to return to their barracks went largely unheeded, although locals said there appeared to be fewer armed men on the streets.
Life in the city began to regain some normality , with traders reopening their stalls under colourful umbrellas and residents venturing out to check on relatives.
"Some activity has resumed. Women stallholders are on the streets making fritters and porridge," one Bangui inhabitant told AFP.
The latest violence appeared to vindicate recent warnings from France, the United States and others that the Central African Republic (CAR) was on the brink of collapse with tensions soaring between its Christian and Muslim communities.
The impoverished country has descended into chaos since a motley coalition of mostly Muslim rebel fighters known as Seleka overthrew former president Francois Bozize in March.
They installed their own chief, Djotodia, as president -- the first Muslim leader of the majority Christian country.
Djotodia formally disbanded the Seleka, but ex-rebels continued to wreak havoc. Local Christians responded by forming vigilante groups and the government quickly lost control of the landlocked country.
Reports have described a litany of horrors, with security forces and militia gangs razing villages, carrying out public execution-style killings and perpetrating widespread rapes.
French President Francois Hollande ordered the launch of operation "Sangaris" -- named after a local butterfly -- after winning a UN Security Council mandate for a peacekeeping force of up to 1,200.
The French troops will help to shore up MISCA, a 2,500-strong African force which is already on the ground but has been unable to stem the country's descent into chaos.
The UN resolution gives the French-backed African force a 12-month mandate and the right to use "all necessary measures" to restore order.
However, UN leader Ban Ki-moon has warned that up to 9,000 troops could be needed to quell violence that has spread through the country of 4.6 million.
As the French reinforcements rolled through Bouar, a mainly Christian town in the west of the country, crowds of cheering residents honked horns, danced and banged on saucepans to welcome them.
"Save us. We have suffered so much," shouted Cedric, 15, in the town, one of France's main military bases in Africa and a nerve centre for the area that saw some of the worst violence at the height of the Seleka rebellion.
"Since they took power we have suffered," said local builder Serge Dilamo.
"There are deaths, they are killing us. Everyone knows someone who was killed."