PARIS -- When Georges Boudarel stepped up to address a symposium on Vietnam at the French Senate recently, the life he had carefully constructed over the last 24 years collapsed before him.
"Are you the Georges Boudarel who ruthlessly ran Camp No. 122?" asked Jean-Jacques Beucler, former chief of the Veterans Affairs Office, who was held prisoner by the Vietminh in the 1950s. "The audience should know what an ignoble man it is dealing with. You have blood on your hands."
Mr. Beucler was mistaken about the camp's identification number. But Mr. Boudarel did not deny the basic accusation against him: In 1953 and 1954, he admitted, he had served as political director of Camp 113 in Mien Nguoc, North Vietnam, responsible for the Communist in doctrination of French prisoners.
Mr. Beucler's very public denunciation has torn open 40-year-old divisions and debates surrounding France's involvement in Vietnam.
It has made allies of Mr. Boudarel's former prisoners and the National Front, the extreme right-wing party of Jean-Marie Le Pen. Leftist intellectuals, meanwhile, are supporting the one-time chief brainwasher in a Communist re-education camp, who has since renounced his Stalinist past and become one of France's most valued experts on Vietnam.
Earlier this month, a group of youths belonging to the National Front briefly occupied the Arc de Triomphe, unfurling a banner demanding that Mr. Boudarel step down from his teaching post at the University of Paris Jussieu campus.
Mr. Boudarel's class, "War and Society," was held at a secret location just over a week ago to keep out "journalists and fascists," one student said.
None of the survivors accuses Mr. Boudarel of physically torturing him. As political director, they said, he brainwashed hungry, overworked prisoners and schooled them in Marxist ways of self-criticism, confession and the denunciation of fellow prisoners.
"He is there, stopped before us, tall, slender and slightly stooped, his eyes surveying the entire brigade as if he was trying to distinguish the weak ones, those who could be influenced," Claude Bayle, a survivor of Camp 113, recalls in his soon-to-be-published memoirs.
In his public statements so far, Mr. Boudarel has apologized for his Stalinist past, but not for deserting to the Vietminh side in 1950.
When he first pointed the finger at the 64-year-old professor, Mr. Beucler said his only goals were to satisfy a pledge to a dead friend to unmask Mr. Boudarel and to bring out the unrecognized suffering of French soldiers and officers in Indochina.
But the campaign against Mr. Boudarel seemed bound to escalate from the start.
Forty leftist intellectuals, many of whom opposed France's efforts to hold onto Vietnam in the 1950s and who praise Mr. Boudarel's expertise on Vietnam, have signed a petition supporting not his past, but the scholar he has become.
On March 20, 18 of his former prisoners at Camp 113 brought suit for crimes against humanity, the only charge not covered by the 1966 amnesty that allowed Mr. Boudarel to return home in 1967. This charge has been used only against Nazis and their collaborators.