The deployment, which is expected to completed later this week if the U.N. Security Council authorizes international intervention to prevent a threatened genocide, will raise the number of French troops in the CAR to around 1,200.
As the French reinforcements arrived in Bangui, the country's ramshackle capital, Sunday, the neighboring Democratic Republic of Congo sent 500 troops to join a 2,500-strong African Union peacekeeping force.
But observers and international aid agencies warn that while these forces should be able to control the capital and its environs without much trouble, they're too few to quell the growing Christian-Muslim bloodletting that many fear could spill over into neighboring states.
French Foreign Minister Laurent Fabius warned last week that the predominantly Christian country of 4.6 million is "on the verge of genocide."
Amnesty International, calling for a "full-fledged U.N. peacekeeping operation," cautioned that the French force is far too small to stem "the horrific cycle of violence" sweeping the country that lies in the heart of Africa.
The U.S. global security consultancy Stratfor observed that "the French forces will likely avoid direct engagement with the rebel forces in the country."
It said "the scale of operations being planned will mostly seek to secure Bangui," and other key towns as Muslim rebels rampage across much of the country, looting, pillaging, murdering and carrying out mass rapes, and clash with Christian self-defense groups.
The CAR has been torn by violence since a loose coalition of five Muslim rebel groups known as the Seleka seized Bangui in March and deposed Christian President Francois Bozize.
The rebels, reinforced by mercenaries from neighboring Chad and Sudan, installed Seleka leader Michel Djotodia in power, the first Muslim ruler in the landlocked country that's been in turmoil more or less constantly since gaining independence from France in 1960.
Djotodia has since renounced the Seleka and declared the alliance disbanded. But he's lost control and the Muslim fighters continue to terrorize Christian communities, which have formed their own militias that claim to be pro-Bozize. There are marauding vigilante groups on both sides.
The country, rich in minerals but mired in poverty because of corruption and poor governance, has fallen into near-total anarchy. All state institutions, barely functioning anyway, have collapsed.
Aid agencies report thousands of people slaughtered or kidnapped, with some 500,000 driven from their homes.
Many of these are reported to be hiding in the jungle without access to medical care or reliable food supply.
Aid agencies report that 1.1 million people, about one-quarter of the population, face acute food shortages. Christians make up 50 percent of the population, Muslims 15 percent.
U.N. Deputy Secretary-General Jan Eliasson says the CAR faces a desperate and horrifying situation.
"The use of child soldiers is rising and sexual violence is growing," he said. "There are widespread reports of looting, illegal checkpoints, arbitrary arrests, torture and summary executions."
His boss, Secretary-General Ban Ki-moon, has urged the Security Council to authorize the dispatch of up to 11,000 U.N. peacekeepers.
The U.N.'s blue berets would bolster the ineffective African Union force drawn from Cameroon, Chad, Gabon and the DRC.
That's supposed to be strengthened to 3,600 men in early 2014, but even if that does transpire, few observers expect it end the bloodletting nationwide.
Fabius warned last week: "If there's a vacuum and implosion, it will affect all the countries of the region -- that is to say, Chad, the Sudans, the Congo and Cameroon," he declared in Paris.
France has appeared reluctant to get involved in the CAR, even though Paris has intervened several times since 1960, the last time in 2006 when it supported Bozize, who'd seized power a year earlier in a coup, against northern rebels.
In recent years, France has adopted a largely hands-off policy regarding its fractious former African colonies.
But in January, Paris sent a 1,400-strong task force, backed by fighter aircraft and helicopter gunships, into northern Mali to drive out al-Qaida-linked jihadists who had established a sanctuary there.