The overthrow last night of Central African Emperor Bokassa, according to clear evidence here today, was arranged and orchestrated by France.

President David Dacko, the new Central African chief of state, said in his first address to his people and the armed forces that, "to aid you in your task, I call upon our constant friend, France."

Two companies of French troops -- 400 men -- arrived in Banqui, the capital of the former French colony, during the night, according to Western sources.

Despite intense pressure to dump Bokassa, French President Valery Giscard d'Estaing had continued to offer the emperor his formal support until mid-August, when an African investigating commission confirmed widespread allegations that Bokassa had taken part in April in the massacre of 50 to 100 school children 8 to 16 years old.

The bloodless coup d'etat took place last night at five minutes to midnight, French officials said. By 8 a.m., the officials said, the French ambassador in Bangui had already seen Dacko and Bokassa's prime minister, Henri Mabdou, who had rallied to the new government, and assured them of French support. The French troops had already arrived, the Western sources said.

Bokassa had been gone for 48 hours, on a visit to Libyan leader Muammar Quaddafi in Tripoli, ostensibly to offer Libya a military base in exchange for the financial aid he needed since France had cut off its financial aid to Central Africa.

Tonight, Bokassa tried to enter France. His plane was denied landing rights at the civilian airports in the Paris area. Finally, it landed at a military base in Normandy but the Elysee Palace said it had landed for refueling only, and that no one would be allowed off.

It was not immediately known where Bokassa might try to go next.

He is a French citizen by virtue of his service as a sergeant in the French Army in Indochina and elsewhere.

"It has all the markings of a negotiated departure," said an experienced diplomatic observer of Bokassa's flight from Bangui.

In Tripoli, Bokassa had joined Uganda's Idi Amin in exile.

Including Equatorial Guinea's recently ousted Masie Nguema Biyogo Negue Ndong, the three Libyan-backed rulers were generally seen as black Africa's most bloodthirsty dictators.

Unlike the earlier coups against Amin and Masie Nguema, the one in Central Africa appeared to have taken place in relatively orderly way, averting civil war and bloodshed.

Diplomatic cables from Bangui spoke of "good-natured but determined looting" that the French troops were bringing under control. It appeared to be directed against shops owned by members of Bokassa's entourage and some French ones, too.

French officials said the two companies of French soldiers appeared to be enough to maintain order and that the troops were being cheered by the population.

Dacko, 49, was Bokassa's predecessor as president from 1959 until Bokassa overthrew him in 1966. Three years ago, Bokassa named Dacko, who is also a cousin, his "personal adviser." But Dacko kept his distance from the ruler who proclaimed his poor landlocked republic of 4 million people the Central African Empire and himself emperor in a sumptuous coronation ceremony in 1977 meant to recall Napoleon Bonaparte's.

French officials expressed great satisfaction over Dacko's restoration of the republic, his pledge of democratic freedoms and his call for the formation of a "public safety government of national union."

Dacko generally is described as having been a mild-mannered and ineffective president. Many veteran observers in Paris expected that his rule would only be an interim one.

Sylvestre Bangui, the former Central African ambassador in Paris who resigned in May after denouncing the children's massacre and who recently announced the formation of a government in exile, offered his support and congratulations to Dacko.

When Bangui formed his government 10 days ago, it was already an open secret in Paris that the French government had made up its mind to support Dacko as the most practical alternative to Bokassa.

Bokassa's wife, Empress Catherine, arrived in France Aug. 23 with their four children, and pictures were published in the French press of her surrounded by bodyguards getting one of Bokassa's three French chateaus into livable shape.

Last week, the French political gossip columns were saying that she had enrolled the children in French schools and that Bokassa had been sending large amounts of money to a bank in Switzerland.

Diplomatic sources said that Bokassa's immediate entourage in Bangui had spent last weekend packing the emperor's papers and belongings at the imperial residence of Berengo, said to be protected by a contingent of Libyan troops.

French president Giscard maintained cordial relations with Bokassa until recently often going on safari to hunt elephants as the emperor's guest.

Bokassa's son Georges, the eldest of his 35 children, recalled in an interview in the magazine Paris-Match this week that his father had entertained Giscard and his son Henri.

Georges, 29, who was expelled to Paris by his father, nevertheless defended him, asserting that his rule was no worse than many in Africa and that its end would only mean warfare among the country's tribes.

He said that his father had turned to Libya and the Soviet Union for help after France canceled about $20 million of its $100 million a year in aid but that this did not mean he was turning toward the east.

Last May, French Cooperation Minister Robert Galley was publicly calling the first reports by Amnesty International of the children's massacre "pseudo-events." But soon after, Giscard attended the French-speaking African summit in Rwanda and privately advocated the investigation by the African jurists' commission. Its report in mid-August on the massacre spelled the beginning of the end. Then, France cut off all aid that was not deemed to be "humanitarian."

More recently, after accusations that Bokassa had staged a new massacre of 40 of the teachers and others who had testified to Amnesty International, the emperor orders his prime minister to assemble the diplomatic corps to hear the emperor's solemn denial, as he had done after the children's massacre. But the prime minister refused.

French interests in Central Africa include a deal to mine the estimated 15,000 tons of uranium ore negotiated for the French atomic energy commission and a Swiss company by Giscard's cousin Jacques.

Giscard's father once owned one of the great trading concessions when Central Africa was part of the hugh colonial territory of French Equatorial Africa along with Chad, Cameroon and Gabon.