Accusations of torture leveled against the leader of France's newly resurgent extreme right, Jean-Marie Le Pen, have ignited a fierce controversy in the media here about the propriety of delving into discreditable episodes of France's recent past.

The accusations against Le Pen date back nearly 30 years to France's last major colonial war in Algeria, which split France into bitterly divided camps from its beginning in 1954 to its end in 1962.

"Tortured by Le Pen," ran the headline across half the front page of Liberation, an independent leftist daily that has sought to emulate American-style investigative journalism. In a special eight-page section, the newspaper published five first-person accounts by former Algerian nationalist guerrilla fighters who described tortures they said were practiced upon them in early 1957 at the orders of Le Pen, then a junior officer in a crack French parachute regiment in Algiers.

The alleged tortures included beatings, electric shock treatment and holding the head of the victim under water. One of the witnesses, Mahfoud Abdelbaki, said he had been forced to watch as Le Pen summarily executed another member of the Algerian National Liberation Front with a revolver.

The controversy surrounding Liberation's revelations has centered not on the issue of whether they are true or false, but whether the newspaper acted in a responsible manner in disturbing the ghosts of recent history. Some analysts said the press polemics could rebound in favor of Le Pen's National Front party which collected 11 percent of the vote at European Parliament elections last June and could do even better in local elections next month.

Writing in the weekly L'Express, one of France's leading political commentators, Yves Cuau, insisted that "the past is past."

"Blowing on the embers of an old tragedy," Cuau added, was not an effective way of combatting the xenophobic ideas of the National Front which has succeeded in attracting large numbers of voters with its emotional calls for tighter controls on immigration and a crackdown against crime.

The rival news magazine, Le Point, commented this week that there was a "quasi-consensus" in France to forget the Algerian "nightmare," with its unhappy memories of hundreds of thousands of French refugees forced to flee the country and the right-wing terrorist backlash against Gen. Charles de Gaulle by the Secret Army Organization.

"Americans have made major films about the war in Vietnam as the English have done about their colonial disengagement. But there has never been a major French film about Algeria," the magazine noted.

Similar inhibitions smothered public debate about another controversial episode in French history: wartime collaboration with the Nazis. A documentary film entitled "The Sorrow and the Pity" which showed the widespread nature of such collaboration was banned from French state-run television for 10 years during the 1970s. It is only now, a generation after the event, that the issues at stake are beginning to be examined.

This ambivalent attitude toward recent history has made it easier for Le Pen to sidestep the allegations of torture and accuse Liberation of seeking to discredit the National Front in advance of next month's elections. He has threatened to sue the newspaper for libel and has also accused the ruling Socialist Party of inspiring a "campaign of intellectual terrorism" against its political opponents.

Perhaps the strongest point in Le Pen's defense is that, like other Army officers serving in Algeria, he was acting under instructions from the government of the day to stamp out an armed rebellion in what was then a department, or province, of France. There is little disagreement among historians that the use of torture by the French Army was fairly widespread at the time as a means of combatting Algerian guerrillas.

"As a result of my actions in the French Army, I was neither investigated nor condemned. In fact I was decorated," recalled Le Pen who already had achieved political prominence in 1956 by becoming the youngest deputy in the National Assembly.

The National Front leader has repeatedly pointed out that a Socialist government was in office during the period in question -- the dying months of the Fourth Republic. Occupying the key posts of minister of justice and minister of the interior was none other than the present Socialist head of state, Francois Mitterrand.

Among the prominent Frenchmen who have come to Le Pen's defense is the former commander of the French forces in Algiers, Gen. Jacques Massu, who argued that all "these unfortunate affairs of 28 years ago" were covered by a 1962 amnesty. Under the terms of the amnesty, which was designed to promote national reconciliation by drawing a curtain over all crimes committed during the Algerian war, Liberation could be convicted of libeling Le Pen even if it can prove that its charges are essentially true.

Asked about the specific allegations of torture made by the five witnesses cited by Liberation, Massu replied: "There is torture and torture. They cannot have been terribly tortured since they seem to be doing very well 28 years later."

This week Liberation published two pages of letters, overwhelmingly critical of its decision to publicize the torture allegations. Typical was a letter from one Jules Duclos, addressed to "a dirty Frenchman if you still are one," demanding that the newspaper investigate tortures of Frenchmen by Algerian nationalists.

The charges and countercharges appear to have embarrassed the Socialist government which evidently feels that torture allegations dating back to the Algerian war are not the best ground for attacking a politician who is beginning to be seen as a serious threat. Prime Minister Laurent Fabius made it clear earlier this week that neither he nor the Socialist Party was going to be drawn into the controversy.

"There is nobody for whom the war in Algeria is a good memory," said the editor of the left-wing weekly Nouvel Observateur, Jean Daniel, who is close to Mitterrand. He recalled that the president had done all he could to "heal old wounds," going so far as to extend the amnesty to pardon the leaders of an attempted coup d'etat against de Gaulle in 1961.

Defending his newspaper's decision to inquire into Le Pen's war record, the editor of Liberation, Serge July, said the public had a legitimate interest in the past of prominent politicians but that investigative journalism was so rare in France that it was almost always seen as an instrument of political manipulation.

"In any Anglo-Saxon country, this would be considered part of the function of the press in a democratic system. In France, it creates a scandal every time," he complained in an editorial.