French President Francois Mitterrand, accompanied by an entourage of journalists, security guards and aides, swept through French-speaking Africa last week like a combination Santa Claus, concerned godfather and chairman of the board.

He pledged more French aid for Africa and continuing moral support at a time of famine and continuing economic hardship. While he was in town, the Burundi government opened its new airport and inaugurated its new state color television network -- both of which were paid for with French gifts and loans.

Both Zairian President Mobutu Sese Seko, who initially threatened not to attend, and Chadian President Hissene Habre, who had complained about French refusal to act against Libyan forces in the northern part of his country, decided to show up and keep their peace after bilateral consultations with the Mitterrand government.

While his style was vintage Mitterrand -- diplomatically correct, overtly sincere, occasionally impassioned -- the substance of the French president's visit reflected what has become a major shift away from Socialist idealism toward a more hard-headed Realpolitik in both his approach and policies toward a continent that remains France's prime sphere of influence in the world.

Mitterrand came to power three years ago promising a dramatic change in French African policy. He pledged to discard the neocolonial, paternalistic, hands-on style of his predecessor, president Valery Giscard d'Estaing, for a more equal, less personalized partnership.

He promised that there would be no more "military adventures" along the lines of earlier French interventions in the Central African Republic, Djibouti, Zaire, Mauritania and Chad. And he made a special point of giving assurances that France, which maintains nearly 9,000 troops and military advisers in Africa, more than any other foreign power except Cuba, would no longer play the role of "the Cuba of the West."

For a while, the new policy matched the rhetoric. Under foreign minister Claude Cheysson, a strong supporter of Third World causes and human rights, and minister of cooperation and development Jean-Pierre Cot, the French talked more about agricultural development than about setting up television networks, and more about civil liberties and free speech than about the Soviet or Libyan threat. Cheysson advocated a harder line toward white-ruled South Africa, and Cot boasted that he never visited an African country without first consulting the international yearbook published by Amnesty International, the London-based human rights organization.

But Cot, the principal exponent of the new Africa policy, left the government in December 1982, reportedly in part over disagreements with Mitterrand's Third World policies. Two weeks ago, Cheysson also departed, leaving French Africa policy firmly in the hands of more pragmatic advisers.

"The French have come full circle on Africa," said a diplomatic observer here. "They've returned to back-scratching and hand-holding the African leaders, and that's what they do best."

The change in part reflects the general toughening of Mitterrand's policies in the past three years as he has completed the transition from opposition leader to head of government. But it also reflects the widespread view in France that the French retain both obligations and prerogatives in Africa that go beyond the ideology of any particular government.

As Pierre Beylan, political correspondent for the right-of-center Parisian daily Quotidien, noted last week, "Africa is the only area where France can play a decisive strategic role. Without its African prolongation, France would not weigh very much on the international scale."

More than any other colonial power, France works hard to maintain a strong presence and influence in Africa. There are more than 300,000 French nationals working in black Africa -- more than were here at the height of the French colonial empire. France remains the dominant trading partner of virtually all of the 15 states that developed from French holdings in Africa. They buy one-eighth of all French exports, and most rely on a French-backed currency system that gives them a monetary stability that is lacking in much of the rest of Africa.

French economic hegemony has declined somewhat in recent years. Where once 65 percent of the Ivory Coast's imports came from France, the figure now is only 35 percent. Japanese Toyotas are as common as French Peugeots, and Sheratons often tower over French-built hotels.

But beyond economics, the French have left their cultural imprint throughout the region. While French influence is sometimes overstated -- few Africans beyond the capital cities speak the language or honor the customs -- it is nonetheless real and powerful.

"When we were in West Africa," says a British character in V.S. Naipaul's African novel, "In a Free State," "you would never have said that the Africans there were remotely English. But as soon as you crossed the border into the French place, there you saw black men just like ours sitting on the roadside and eating French bread and drinking red wine and wearing little French berets."

It is a tie that often seems to surmount ideology. The People's Republic of Benin is French-speaking but calls itself a Marxist-Leninist state, welcomes Soviet and Libyan assistance and regularly denounces European "imperialism." Yet the air traffic controllers at Cotonou's international airport are white Frenchmen.

The annual Franco-African summit is a monument to French influence. In 11 years it has grown from a small, informal gathering of French-speaking Africans into a major event attended by more than 40 African states.

But this year's conference also underlined the limits of French power and ambition. Several African leaders, including the Ivory Coast's Felix Houphouet-Boigny, the senior patriarch of French-speaking Africa, chose not to attend, in part to protest French policy in Chad. Nonetheless, the French stuck to their public position that unless Libyan forces cross into southern Chad, France will not order its troops back into the country. Although Mitterrand's aides denied it, France seemed prepared to allow Libyan leader Muammar Qaddafi to renege on his commitment for a withdrawal of his forces from Chad and to tolerate a de facto partition of the country.

That position left many conservative African leaders, who fear Qaddafi's influence in their own countries, looking unhappy. But no one was prepared to speak out publicly against Mitterrand.