The success shines. By working out an agreement with Libya to pull French and Libyan troops out of Chad, French President Francois Mitterrand has staged a diplomatic coup that strengthens his position at home and abroad.
At home, Mr. Mitterrand received cheers from both the conservative opposition and the disgruntled Communists. As the French presence in Chad dragged on more than a year with no end in sight, criticism had been growing that France was being dragged into a quagmire. But Tuesday, even virulent antigov-ernment editorialist Phillippe Tesson of Le Quotidien applauded the President's ''agile'' maneuvering.
Politically, Mitterrand needs such a boost. With his economic austerity program unpopular, he has been trying to portray himself as a statesman, representing France on the international stage with both dignity and courage. Elysee Palace advisers say such claims will be at the center of Socialist electoral strategy for the 1986 legislative elections.
The Chad success is just as important abroad. Not only does it hopefully check Libyan adventurism and end the danger of a violent Libyan-French confrontation, but also it safeguards Paris's close ties with its former colonies in Africa, ties from which France draws large economic and political benefits. Mr. Mitterrand himself insists that France's special relationship with Africa continues to make it a world power.
Most countries in Francophone Africa, including Chad, have bilateral security agreements with Paris. When Mitterrand originally hesitated in deploying troops last year, such important African leaders as Ivory Coast's Felix Houphouet-Boigny and Gabon's Omar Bongo publicly expressed fears.
Now they seem reassured. A flow of effusive statements has been noted with pleasure here, especially the bravo from the Marxist, anti-French President of Bourkina, Fasso (Upper Volta) Thomas Sankara: ''France has written today a new type of military treatise, the title of which should be, ''The art of pulling oneself out of the sand.''
Officials here see diplomatic benefits beyond black Africa, in the Maghreb (the strip of North Africa bordering the Mediterranean), and even with the United States. Mitterrand had scared the Algerians and Tunisians while conducting his secret diplomacy with their enemy, the Libyans.
But the announcement of the agreement itself has seemed to calm their fears of a French double cross. The Algerian government reacted with ''satisfaction,'' calling the accord ''the beginning of a response to one of African's pressing problems.''
The American response was much more cautious, but the French are not perturbed.
They note that the Americans were pleased by the original dispatch of troops to Chad and supported the French during the long stalemate in the desert. American officials here always have taken a similar line, saying that having the French police Africa saves Washington undue difficulties in the region.
American caution comes from a mistrust of Colonel Qaddafi. The French say that the Americans are ''obsessed'' with the Libyan leader, and that toughness combined with talk can move him to reason.
The present agreement is a result of just that. And Qaddafi, finding his occupation of northern Chad expensive and divisive, finally budged.
Still, the French do agree that caution is needed to make sure the Libyans do not again invade Chad. Officials here stress that French soldiers can easily return to the desert.
The airport at N'Djamena, Chad's capital, has been enlarged to receive large transports, and after their withdrawal, French troops will stay in the neighboring Central African Republic instead of returning to Europe.
But what does this all mean for Chad?
Analysts here note that the agreement about Chad was made without Chadian participation.
The French-supported government of Hissein Habre greeted the Libyan-French accord with suspicion.
Foreign Minister Gouara Lassou, in Paris, said he learned the news from the press, adding, ''We don't believe the Libyans.''
Meanwhile, the French hope that a peace conference sponsored by the Organization for African Unity will be held soon in Brazzaville, Congo.
If their seemingly improbable peace with the Libyans can hold, they ask, why can't there be a surprise peace among the Chadians as well?