"That's where it is. That's my prison, " he said, walking toward No. 10 at the end of a row of cells -- now storage units -- lining both sides of the courtyard.
Stepping inside, Duval said, "Shut the door." Seconds later, it slammed opened again.
"It's very emotional, " says Duval, 53, a stocky man who now runs a feeding and sports outreach program for 1,300 children in the capital's Cité Soleil slum.
The paint inside is peeling and the cell is choked with cobwebs. Scrawlings on the metal door hint at the desperation its inmates must have felt.
"St. Yves and St. Joachin, my attorneys, deliver me, " wrote one ex-prisoner.
"St. Joseph, father of orphans, defend your children in this, " wrote another.
"People like to say that when Duvalier was in power there was security. There was no security, there was total insecurity, " said Alix Fils-Aimé, 58, once jailed in the cell across from Duval.
Fils-Aimé, who now heads the government commission to disarm Haiti's violent street gangs, says he spent some 15 months in the Dessalines cells after his April 1976 arrest, accused of plotting against the regime. He, too, was released at Carter's request.
"I grew stronger every day I was in there, " said Fils-Aimé, noting that while he no longer is angry, it's difficult to put his emotions into words. "It's revolting to think of how the whole country was submitted to that horror."
Despite such memories, it appears that the younger Duvalier, who has lived in exile in France since he was forced to flee, and his supporters are trying for a comeback.
This fall, Duvalier issued a recorded speech from France in which he said that "if, during my presidential mandate, the government caused any physical, moral or economic wrongs to others, I solemnly take the historical responsibility . . . to request forgiveness from the people."
Préval told The Miami Herald that under Haitian law, Duvalier has a right to return -- but he must be prepared to stand trial.
The apology came as Duvalier's political supporters, with his French girlfriend guiding them, have been quietly campaigning to clear the way for his return by attracting a new generation of followers.
"It's not a question about looking toward yesterday, it's a question of looking at the mistakes of yesterday and those that are being created today and fixing them so that we can have a better tomorrow, " said Stanley, a supporter of Duvalier's National Unity Party who declined to give his last name but said he was 30 years old.
NOT JUST MISTAKES
Those who lived through the Duvalier era recall much worse than "mistakes."
If today's Haiti is still struggling with extreme poverty and a weak democracy, it is because it was already spiraling downward by the end of the Duvalier regime, said Bernard Diederich, a retired journalist who lived in Haiti during part of the Duvalier years and has authored several books on the subject.
Under Duvalier, the country lost most of its teachers and other professionals, and suffered from such widespread corruption that Haiti was left "an intellectually handicapped country, " Diederich said.
"What we are seeing now is the result of those 30 years of dictatorship, " said Diederich, 81, who lives in Miami. "There was nothing good about those days. . . . Those who have nostalgia are idiots."
Newspaper publisher Elsie Ethéart agrees. She was among 21 journalists jailed at the Dessalines barracks in 1980. Expelled from Haiti by Baby Doc, she said there is nothing to be nostalgic about.
"To the contrary, some of the people who sent me to jail are coming back to live in Haiti today. It is hard for me to be 'nostalgic' about that period, " she said.
This is not the first time the government has tried to preserve a symbol of the Duvalier era.
Several years ago there was an unsuccessful attempt to save Fort Dimanche, where political prisoners were executed.
Determined to spare the Casernes Dessalines from the same fate, Préval says he wants to transform it into a museum where school children can see what they call "a ruthless dictatorship."
"We need to remind them of the history, " he said.