In 19 relatively tranquil years, the Ivory Coast has progressed from a backwater of France's colonial empire to become one of black Africa's premier examples of prosperity and stability.

In Africa, where many newly independent states have undergone destructive upheavals or had elected government overthrown in bloody military coups, the Ivory Coast has survived the taut ethnic and tribal rivalries that have left other states in economic ruins.

Felix Houphouet-Boigny, 74, the flexible but stern president of the Ivory Coast since independence, has run the country through tight control over a pervasive, paternalistic one-party system of government that embraces the country's 60 tribes, the trade unions and university students -- all potential sources of opposition.

Now, in line with a trend toward political liberalization in West Africa, Houphouet-Boigny has announced that he will reform the structure of the Democratic Party of the Ivory Coast to allow more grass-roots participation in the country's affairs.

Since independence, all political candidates for the 120-member National Assembly and municipal offices have been chosen by the party's 70-member Political Bureau, which is dominated by Houphouet-Boigny.

In the Dec. 7 independence day speech in which he announced the reforms, the president struck a rare populist theme. The generally conservative Houphouet-Boigny told thousands of Ivorians that the time had come to decentralize the party's control in the country. The speech's theme has generated excited speculation among the country's 7.5 million people. t

"We have become a mature people," said Houphouet-Boigny, "and the people should be allowed to choose democratically at all levels."

The revemping of the party will take place by June and be followed by national elections in the fall. Houphouet-Boigny said he will be a candidate for reelection.

Houphouet-Boigny's decision follows closely the return of elected civilian rule in two neighboring countries, Ghana and Nigeria, in September and October. It is unclear whether the well-publicized changes had any impact on the Ivorian leader's decision, but serveral knowledgable observers said the recent transitions did not go unnoticed here.

"We have had a problem of national unity," said one of Houphouet-Boigny's closest political associates, Mathieu Ekra. "That is why the party was given so much power and some people may have abused it.

"But now, the idea of belonging to one nation has been achieved, so the tight controls can be loosened," Ekra added.

Because it has one of Africa's few successful economies, the Ivory Coast has attracted cheap African labor from its neighbors and a large community of French citizens whose positions and high salaries have caused some resentment here.

As in many Third World countries, the political and economic fortunes of the Ivory Coast have been organized around one man and his philosophy of a mixed economy of state-run enterprises and capitalism.

With a cash crop base of coffee and cocoa, the Ivory Coast has enjoyed a dramatic average economic growth rate of 7 percent annually, the highest in black Africa. It annual per capita income of $1,100 also the highest, is the most equitably distributed in all of Africa, according to World Bank studies.

Unlike a number of his neighbors, Houphouet-Boigny resisted the general postindependence rush to industrialize and concentrated his government's efforts on agricultural growth. While his neighbor's fledgling industrial efforts and economies faltered, the Ivory Coast prospered.

Almost 2 million Africans have flocked into the Ivory Coast for low-paying work on the coffee and cocoa plantations and in Abidjan. Many have come from the country's poorer neighbors, such as Ghana, Mali, Upper Volta, Niger and Guinea. Although they compete with some Ivorians for jobs, while the economy has remained robust, their presence has not caused any major unrest.

One possible source of tension here is the presence of an estimated 60,000 French in Abidijan, many of whom work in executive positions in government and private industry. This is a sore point with many Ivorian university graduates and students.

"One of every four Frenchmen in Africa lives in Abidjan," said a French official in charge of government aid to former colonies.

"We think it is too much and it creates problems, but Houphouet wants them there," the official recently said in Paris.

"We all know that it's a problem," said Houphouet-Boigny's troubleshooter Ekra, "but we are faced with a conflict."

Young Ivorians, Ekra said, are in a hurry to replace the French but the government does not feel that enough of them have sufficient experience. "We have to keep the economy going," he added.