At mid-morning, the unblinking Caribbean sun already has nearly blinded the city. From the outside, the white walls of the National Palace hit the eyes like a slap.

Inside, tucked into a second-floor corner, the executive office is a dark and frigid cave. The curtains tightly drawn, Haiti's President for Life sits at a solid marble desk beneath a picture of his father, Francois "Papa Doc" Duvalier.

It is now more than seven years since Jean-Claude Duvalier, at the tender age of 19, replaced the dead Papa Doc as the most powerful man in this small island nation.

In the interim, he has lost much of the baby fat that was his most distinguishing physical characteristic on taking office. His soft voice, although often barely audible during a recent interview, was self-assured and humorless.

Duvalier has given few interviews since his assumption of the presidency. The Haitian media confine themselves to government handouts and speech reprints, and the U.S. media, he said, know that it "pays to emphasize the sensational." By "distorting the reality of Haiti," he said, they "disturb the social and economic development of the country."

"Since our means are rather limited," Duvalier said, "until now we have not made an important effort to counteract" Haiti's world image as an undeveloped backwater ruled by corruption and the whim of the 21-year Duvalier dynasty.

Recently, however, Haiti followed the lead of a number of Latin American countries in hiring a U.S. public relations firm to tell the world, as the agency says in its first publicity handout, that "the story of Haiti today is change."

Central to that change, according to Haitian officials and the public relations specialist, is the transformation of "Baby Doc," as he was originally dubbed by local wags and an amused world, from what one long-time foreign observer here called an "overweight kid with scared eyes and surrounded by protective guns" into a mature leader capable of bringing Haiti into the 20th century.

If anything, however, the spread of local stories about the 26-year-old bachelor president's personal life and political style has increased rather than diminished in recent years. His reported fondness for fast women and fast cars, his million-dollar yacht and his use of the palace courtyard for a motorcycle race track are subjects of endless gossip here - admiring and derisive.

On whirlwind trips through the countryside, it is said, Duvalier sometime carries a big "macoute" - a knapsack full of money that he tosses to peasants. Haitians who claim to know about such things say his picture adorns voodoo altars in rural villages.

In Haiti, where palace intrigue takes the place of party politics, there is constant speculation on who really runs the country - Jean-Claude, his powerful mother, or one of a handful of characters with unclear duties and titles like "chief of political police" and "commander of the presidential guard."

Personally chosen by his dying father as successor, Duvalier was installed by virtue of a constitutional amendment changing the presidential age from 40 to 18, and a national referendum in which 2.4 million Haitians approved him, and none were opposed. Both the question - "does this choice satisfy your aspirations?" - and the single answer - "yes" - were printed on the ballot.

Still, Duvalier insisted, he never wanted the job.

"I'll give you exactly the reactions that I had when my father called me to him." DuValier said. "I told him, Dad even thought you hand over this office to me on a diamond plate, it is not my sincere wish.'"

But, he added: "When I became aware of the situation. I saw there was no solution for me. Otherwise, there would again be civil strife in this country. I have already given my life" to Haiti.

The new young president took over a crippled economy, a starving and illiterate population, and the reins of a family dictatorship considered among the bloodiest and most repressive in this country's turbulent and tragic history.

Despite the publicity claims, there has been little visible change since then. Crowded into the mountainous, poorly soiled western third of the Caribbean island of Hispaniola, which it shares with the Dominican Republic, the vast majority of Haiti's 5.5 million people are still among the poorest and least educated in the world.

While things are noticeably less bloody and arbitrary under Papa Doc's son, the reins of repression are still tightly held and dissent is only minimally tolerated. The country is still an economic shambles, with foreign aid now providing approximately 65 percent of its development budget.

While speculation continues about him and his role in the government, many observers here agree that Baby Doc, at least in some ways, has grown up. Last January, he announced the formation of his own political and social movement, replacing the all-encompassing "Duvalierism" begun by his father. It is called "Jean-Claudism."

"The late Dr. Duvalier," whose administration was marked by constant suspicion of conspiracy and frequent government purges, was occupied by "problems of a political order," the young Duvalier said. "Consequently, (he) never had the time to takecare of to give 100 percent attention, to the administration of his country."

"It now falls on my shoulders." Duvalier said, "to materialize all the projects that he dreamed about."

Although his opponents privately charge the government with using the threat of "chaos" as a bogyman, there is little question that, despite his means, Papa Doc brought a certain type of stability here that has continued under his son.

"In the 10 months before Papa Doc," argued a high-level Haitian official, "between December 1956 and September 1957, we had eight governments here." People remember that time with horror.

"I never thought I could stomach a 26-year-old dicatator," the middle-aged career official said, "but we had no alternative then, and still don't. When people tell us we should have elections here. I have to ask if they're joking or have a total misconception of reality."

"He likes foreign cars, that's true" the official said. "He likes beautiful women. But we have to concede him some pleasures in accordance with his youth."

Asked about the wisdom of such publicly expensive tastes in such a poor country, Duvalier asked. "Why is it normal for other people to have cars and abnormal for me" I am not the only person in Haiti who has a yacht."

Duvalier bristled at the suggestion, offered by many Haitians, that his mother Simone and a group of powerful old-guard Duvalierists popularly known as "the dinosaurs" rule him with an iron hand.

"The president of the republic has absolute control of his administration," he said. The first lady, "my beloved mother . . . takes care only of the social works of the government, the poor people and abandoned children."

Still, a Haitian official offered diplomatically, Mrs. Duvalier "has about as much control (over Jean-Claude) as a mother can have over a good son."

Duvalier said he considers development Haiti's highest priority. With an estimated 80 percent illiteracy, one of the world's highest infant mortality rates, severe overpopulation, limited capital and even more limited resources, there is no shortage of potential development projects.

The president said he plans to attack all them with the help of foreign aid that has, according to U.N. figures, increased more than 800 percent over the past four years. Haiti's combined development and operations budget totals $257 million for 1978 and projected aid for the next three years is $600 million.

But nearly half the government's internal revenues are unbudgeted and deposited into what one foreign aid official called an unaudited "presidential slush fund." Haiti's international donors, particularly the United States, which plans to double this year's $20 million program next year, have insisted on fiscal reform.

While Duvalier said fiscal change may be coming, he made it clear that political change was not. Describing himself as "a good pupil of the late Dr. Duvalier," the president said the has no plans to diminish the strenght or power of the National Security Volunteers, the thousands-strong civilian militia previously known as the Tontons Macoutes, that formed his father's personal security force and ruled the countryside through terror.

While the militia still exists in greater numbers than ever, it has cleaned up its image somewhat. Its members no longer prowl the streets with bulging guns tucked in their belts, and the opaque sunglasses that were once their trademark have largely disappeared.

Although the military prison at Port au Prince's "Caserne Dessalines" has replaced the infamous Fort Dimanche as the main stronghold for political dissidents, the government claims that its last political prisoner was released in a general amnesty last year.

Last month, Duvalier hosted a visit here by the Inter-American Human Rights Commission. The president has personally guaranteed that there will be no reprisals against those who showed up to tell the commission of rights abuses.

Two opposition newspapers openly began publishing last year for the first time under the Duvaliers, but their success has been mixed. While one continues in operation, the second closed last December after its publisher received a near-fatal midnight beating at the hands of the militia.

Although he is installed in his own job for life, Duvalier said elections for Haiti's unicameral legislature will be held "early next year," for the first time since 1971. Although he noted that the constitution does not prohibit political parties, Haiti has none. No one other than recognized Duvalierists has run for office for the last 20 years.