France "bears significant responsibility" for enabling the genocide in Rwanda and still refuses to acknowledge its true role in the 1994 horror, said a report commissioned by Kigali that was released on Monday.
The damning report, commissioned in 2017 and nearly 600 pages long, calls France a "collaborator" of the extremist Hutu regime that orchestrated the pogrom of about 800,000 people, and outright rejects that Paris did not know of their genocidal agenda.
But both countries appeared keen to turn the page on years of often poisonous ties.
A French presidential source praised the fact that complicity in the genocide was excluded and said the report would "open a new political space" between the two countries.
Meanwhile a statement from the Rwandan Cabinet looked forward to "the prospect of a new chapter in the relations between France and Rwanda".
The years-long investigation by US law firm Levy Firestone Muse said France knew a genocide was coming but remained "unwavering in its support" of its Rwandan allies, even when the planned extermination of the Tutsi minority was clear.
"The French government bears significant responsibility for enabling a foreseeable genocide," said the report, which drew on millions of pages of documents and interviews with more than 250 witnesses.
But it found no evidence that French officials or personnel directly took part in the killing of Tutsis.
France has long been accused of not doing enough to halt the massacres, and the report follows the publication last month of a separate inquiry into the same events, commissioned by French President Emmanuel Macron.
The Duclert Commission, named after the historian leading that investigation, concluded that France bore "overwhelming responsibilities" over the genocide and acknowledged a "failure" on its part, but no complicity in the killings.
But the latest report asserts greater French culpability, saying the Duclert Commission stopped short of explaining what France was responsible for, and erred in concluding that Paris "remained blind" to the looming genocide.
"The French government was neither blind nor unconscious about the foreseeable genocide," the report stated.
Rwanda's Foreign Minister Vincent Biruta told Le Monde newspaper that his country would not seek legal action against France.
"The main thing is that the two commissions come to common conclusions, that France has ... heavy and overwhelming responsibilities (and) allowed a genocide which was foreseeable to take place," Mr Biruta said in Kigali.
The genocide between April and July of 1994 began after Rwanda's Hutu president Juvenal Habyarimana, with whom Paris had cultivated close ties, was killed when his plane was shot down over Kigali on April 6.
Within a few hours extremist Hutu militia began slaughtering Tutsis, and some moderate Hutus, with a scale and brutality that shocked the world.
The report said nobody worked closer with Mr Habyarimana than France under then leader Francois Mitterrand, who was most to blame for the "reckless enabling" of the radical Hutu regime as it prepared for genocide.
France provided critical military and political support to the regime to protect its own strategic interests in Africa, the report said, and ignored internal warnings of a slaughter even as violence against the Tutsis surged.
"Only the French government was an indispensable collaborator in building the institutions that would become instruments of the genocide," the new report said.
"No other foreign government both knew the dangers posed by Rwandan extremists and enabled those extremists.
"The French government's role was singular. And still, it has not yet acknowledged that role or atoned for it."
President Paul Kagame, who has led Rwanda since the end of the genocide, welcomed the recent Duclert Commission as "an important step toward a common understanding of what took place".
But Mr Kagame said a decades-long effort by France to avoid responsibility had caused "significant damage".
The new report accused France of concealing documents, blocking justice and spreading lies about the genocide in a deliberate campaign to "bury its past in Rwanda".
"The cover-up continues even to the present," the report said.
It said French authorities refused to co-operate with the inquiry or turn over critical documents pertinent to their investigation.
On April 7, the 27th anniversary of the start of the genocide, France ordered the opening of key archives concerning the work of Mitterrand between 1990 and 1994, including telegrams and confidential notes that were sources in the Duclert investigation.
The Muse report noted that the recent disclosure of some documents related to the Duclert Commission suggested "a move toward transparency".
