Paris — It was billed as a love bash in Bujumbura, exulting in the close ties between France and its former African colonies. Instead, French President Francois Mitterrand faced a set of angry allies during the 11th annual Franco-African summit, held Tuesday and Wednesday in the exotically named capital of Burundi. France's very role as military protector and commercial partner was being questioned - with potentially important implications for American interests on the continent.
The immediate, decisive issue is Chad. In the African view, Mr. Mitterrand has acted weakly, permitting Libyan troops to continue occupying the north of the country after French troops pulled out. Three prominent Francophone leaders, the Ivory Coast's Felix Houphouet-Boigny, Niger's Seyni Kountche, and Benin's Mathieu Kerekou, refused to attend the summit, reportedly in large part because of anger over Chad.
''It worries me,'' Zairian President Mobutu Sese Seko said to reporters during Mitterrand's weekend stopover in Zaire. ''The Libyans haven't budged and they don't respect a withdrawal document that engages them.''
The criticism didn't move Mitterrand.
''We will continue to play the diplomatic card,'' a French official here confided.
Despite denials, the statement suggests a French willingness to accept a de facto partition of Chad. If the Libyans move south, though, officials insist French troops will return and go on the offensive. This threat, French officials argue, ''dissuades'' Libya from further attacks.
At the same time, Mitterrand suggested in Bujumbura that the Africans should stop complaining and act positively in Chad. He demanded a diplomatic effort to achieve a political settlement between warring Chadian factions. The French say such a settlement would stop Libyan adventuring south of the Sahara.
''France will continue to offer support, including military support, according to the contracts it has signed,'' Mitterrand told the African leaders. ''But also, the first condition is that you try to realize your own unity.''
''We are willing to help,'' a French official said. ''But the Africans also have to help themselves.''
Telling the Africans to help themselves marks a change in tone at least in France's relations with its former colonies. Much more than Britain, the other great imperial power, the French have remained in their former colonies. About 8 ,000 French troops are stationed on the continent, ready to intervene as they did in 1977 and 1978 in Zaire. Economic bonds are just as strong. French African currencies are tied to the French franc.
The close links serve French commercial and strategic interests, and perhaps more important, its national pride. In Africa, at least, France remained the superpower, occupying a useful role from the American perspective.
''The French play gendarme for Western interests,'' explains an American diplomat here. ''There is no secret that this pleases us.''
But the Chad episode, and the morose atmosphere at Bujumbura, have raised doubts about France's ability to keep playing gendarme in Africa. France, after all, suffers from deep economic ills, leading to suggestions here that Paris is too weak to maintain its Africa connection.
The Africans themselves seem to be raising the issue by seeking closer ties with the United States. Within the past two years, several leaders, including Zaire's Mobutu and Ivory Coast's Houphouet-Boigny, have visited the White House. Niger's Kountche visited on Tuesday.
French officials become aggressive when asked about the US role in Africa.
''The Americans are only interested in Libya,'' one official said. ''They don't care about Chad or Africa.''
In contrast, Mitterrand told the Africans that France remains the best partner for their development. He evoked France's key role in negotiating the new Lome development treaty with the European Community, and the French proposal that the World Bank create a special development fund. He concluded by saying that France has increased its aid to the region in the past few years.