The most prominent political victim of France's Greenpeace scandal, Charles Hernu seemed a lonely, defeated man when his official bulletproof Citroen whisked him out of the Defense Ministry in Paris for the last time back in September.

Today, three months later, the disgraced former minister has become accustomed to receiving ovations whenever he appears in public. Buoyed by about 20,000 sympathetic letters that he has received since his forced resignation, he is even dropping hints about running for president.

Newspapers that wrote Hernu's political obituary last September after he was officially blamed for the bungled sabotage of a Greenpeace ship in New Zealand by French secret agents are now running articles analyzing a remarkable political comeback.

"Hernu superstar! Who would have believed it?" marveled the illustrated weekly Paris Match. "Hernu takes off," gushed Le Nouvel Observateur, a highbrow journal for left-wing intellectuals. "What's happening to Charles Hernu?" asked L'Express, France's leading news magazine, as bewildered as most of its readers.

The latest twist in Hernu's fortunes provides an unexpected epilogue to France's most serious political scandal since the left came to power in May 1981. Senior Socialist Party officials privately accused Hernu of concealing the truth about the Greenpeace sinking from President Francois Mitterrand for more than two months to protect the Army and the secret services.

It took a long series of damaging press revelations and a criminal investigation in New Zealand before France conceded that its own agents had sunk the Greenpeace ship Rainbow Warrior in order to forestall a protest against French nuclear tests in the Pacific. Two French Army officers are now serving 10-year prison sentences in New Zealand after acknowledging involvement in the sabotage operation, which resulted in the death of a Greenpeace photographer.

The former defense minister's return to favor also points up the contrast between the political mores of France and the United States. In America, a government official accused of covering up a criminal operation would be lucky to escape without a prison sentence. In France, such officials can wind up being praised for patriotism if they play their cards right.

The epicenter of the Hernu phenomenon is Villeurbanne, an industrial suburb of Lyon in southeastern France. A grimy town of 120,000 inhabitants with deep-rooted left-wing traditions, it has been regarded as Hernu's political fiefdom since 1977, the year he was first elected mayor. His natural place of refuge at the moment of disgrace, the town is now serving as a trampoline back to national attention.

In France, a politician may retain local elective office while serving in the national Cabinet, and Hernu kept his job as mayor.

At the age of 62, Hernu has embarked on a daily round of inaugurating Christmas trees and opening village fire stations with the gusto that he used to reserve for launching nuclear submarines and reviewing French troops. Easily recognizable thanks to his thin reddish beard, he plunges into crowds, kissing ladies, signing autographs and pinching the cheeks of babies.

The word "Greenpeace" scarcely ever intrudes into this jovial atmosphere, which combines the characteristics of an extended family and a political campaign.

From the perspective of Villeurbanne -- a typical enough town in what is known as la France profonde, real, "deep" France away from the hothouse political atmosphere of Paris -- Hernu is the good soldier who lost his job because he kept his mouth shut.

"No one here considers that he was really responsible for the Greenpeace affair," remarked Francois Lozano, watching the mayor open a new indoor bowling park. "The real responsibles were the higher-ups: Mitterrand and Prime Minister Laurent Fabius. But they told Hernu to take the blame."

Hernu's first step back to political rehabilitation came when local party activists chose him to head the Socialist campaign in the surrounding Rhone region for legislative elections next March. He followed this up with an announcement that, if the Socialists do well in the Rhone next year, he will consider running for president in 1988 provided Mitterrand does not seek reelection.

An opinion poll earlier this month reported that 35 percent of French citizens wanted Hernu "to play an important role in the future." This makes him the fourth most popular Socialist politician, a status that he never approached before the Greenpeace affair. Ironically, he is now nearly as popular as Fabius, the man who forced him to resign as defense minister.

The French press has been full of stories about special gestures of affection for Hernu among the military. Readers have been regaled with anecdotes about soldiers spontaneously lining up to form an honor guard for the ex-minister at the Gare de Lyon in Paris, about a standing ovation at an Army ball, about officers snapping to attention when they meet him in the street.

"It's embarrassing; I wish the press would not write about these things," remarked Hernu, who then proceeded to tell a visiting journalist a story about how, only the other day, a local Army contingent insisted on according him the honors due to a defense minister.

While Hernu is clearly adept at handling his press relations, he seems to be entirely genuine in his love affair with the Army. The son of a modest gendarme, he has devoted his political career to overcoming the traditional mistrust between the Socialist Party and the Army. He played an important role in persuading Mitterrand to reverse his opposition to France's nuclear deterrent, the force de frappe.

"I was the symbiosis between the Army and the nation," said the ex-minister proudly, hinting that this is the reason why his enemies were keen to get rid of him.

Hernu's passion for the military is reflected in his office in the Villeurbanne town hall. The display cabinets around the room are stuffed with model airplanes, tanks and other military trinkets collected during his 4 1/2 years as minister of defense. A bronze representation of Saudi Arabia defended by French antiaircraft systems -- the gift of a Saudi prince -- occupies a prominent place on his desk. Next to it is a penholder presented to Hernu by U.S. Defense Secretary Caspar W. Weinberger.

Presiding over a golden wedding anniversary between two Villeurbanne residents, Hernu unearths the fact that the proud husband served in the Army for 26 months as a youth, reaching the rank of corporal. This obscure biographical detail provides him with the pretext for a rhetorical detour into the importance of Franco-American military cooperation in West Germany.

The unashamedly patriotic image cultivated by Hernu has helped deflect embarrassing questions about Greenpeace. There has been remarkably little moral outrage in France about the secret service operation against the Rainbow Warrior. Many French citizens take the view that the government was justified in taking action to prevent the disruption of its nuclear testing program. The real crime was getting caught.

"Hernu is a French version of Rambo," commented an editorial in Le Nouvel Observateur, remarking that the former minister "incarnated" the return of patriotism at a time of ideological confusion.

The upsurge of stories about Hernu's political comeback has overshadowed lingering questions about his role in the Greenpeace affair. He simply refuses to answer such potentially embarrassing questions as why, just before his resignation at a time when he must have known about French involvement in the sabotage operation, he issued a statement formally denying that French agents were responsible.

"My conscience is clear," he repeats over and over again, like a magical incantation.

When pressed, Hernu says that he resigned because he was politically responsible for the secret services. But he denies giving an order to sink the Rainbow Warrior.

A continuing mystery is how Hernu has managed to remain on excellent terms with Mitterrand if he really did mislead the president on Greenpeace. Asked how he felt about the former defense minister at a recent press conference, Mitterrand replied: "Hernu was, is and remains my friend."