This morning, near Paris, French police arrested Agathe Habyarimana—the former first lady of Rwanda—on a seven-count international arrest warrant issued by the Rwandan government. The charges: genocide, complicity in genocide, conspiracy to commit genocide, creation of a criminal gang, murder and conspiracy to commit murder, extermination, and public incitement to commit genocide.

Madame Agathe, as she was known in Rwanda when she had power there, has long been closely identified with the hard-core of Hutu Power extremists who planned and orchestrated the genocide of Rwanda’s Tutsi minority in 1994. Le Clan de Madame, her court within the court, was known as the akazu—the little house. The members of the akazu were the masterminds of the extermination campaign, and before, during, and after the killing they enjoyed the patronage and protection of France, whose role in the genocide was as unambiguous as its official denials over the years have been unconvincing.

When the slaughter broke out, after the assassination of President Juvénal Habyarimana, in April of 1994, French soldiers whisked Agathe Habyarimana into exile, and for the past decade she has lived unbothered in France—although French courts have consistently denied her bid for political asylum, on account of her reputation as the Lady Macbeth of the Rwandan genocide. Rather than owning up to its disgraceful past in Rwanda, successive French governments have always—until now—preferred to accuse Rwanda’s post-genocide government of having instigated the genocide, when in reality it brought it to a halt. That is what makes France’s arrest of Madame Agathe such “huge news”—as a press officer for Rwanda’s President Paul Kagame described it today.

When Rwanda issued the warrant for Madame Habyarimana’s arrest, on October 19th last year—and delivered it to Interpol and to French authorities—Rwanda and France were officially in a state of diplomatic hostilities. There had never been any love to lose between the two governments since 1994, but the rupture came three years ago, when a French judge had accused President Kagame of assassinating President Habyarimana, and had indicted a number of Kagame’s associates for the crime. Kagame’s response to the French indictments was to break off relations with France, and to prepare a series of reports showing how, in fact, the French political and military establishments had a great deal to answer for and a great deal to hide in their Rwandan pasts. Beneath the legal and diplomatic combat, however, Kagame opened the back-channel contacts with President Sarkozy that led, late last year, to a restoration of relations and a reopening of embassies, followed, five days ago, by a visit to Rwanda by Sarkozy himself, making him the first French president to do so since the genocide. (Listen to the press conference.)

French statesmen are not in the habit of travelling to small African countries that they used to run as puppet regimes to eat fistfuls of crow. But that is precisely what Sarkozy did last week when he stood beside Kagame in Kigali and declared that France had made mistakes during the genocide, and had to reckon with them. Afterwards, commentators made much of the fact that Sarkozy had not issued a full apology. But in a country whose history is still bloodily contested, Sarkozy’s frank acknowledgment of the truth of his former antagonist’s reality sent an unmistakable message. Without France’s cover, the pretense that Rwanda’s genocide is an open question is stripped barer than ever.

With this morning’s arrest, we can see that France’s change of attitude toward Rwanda was at least partly influenced by the facts presented in the case against Madame Habyarimana. In November of last year, a pair of French judges went to Kigali to study the evidence assembled by Rwanda’s Genocide Fugitives Tracking Unit. Meanwhile the French case against Kagame’s coterie appeared to be crumbling. Whether France will extradite Madame Agathe to Rwanda remains to be seen. She has already been released on bail. But such is the warm mood between the two governments that Rwanda’s prosecutor general, Martin Ngoga, declared today that he had every confidence in the French judiciary—a statement that was simply unimaginable from a Rwandan official six months ago.