A witness says his testimony was distorted by a French inquiry which accused Rwandan President Paul Kagame of killing his predecessor.
Mr Kagame said the allegations were politically motivated
Former Rwandan soldier Emmanuel Ruzigana denies admitting to being part of a group that assassinated the president, reports a French newspaper.
Earlier, Mr Kagame accused France of "bullying" his country after a judge issued arrest warrants for his aides.
Rwanda has cut off diplomatic relations with France over the accusations.
The 1994 shooting down of the plane carrying former President Juvenal Habyarimana sparked the genocide, in which some 800,000 ethnic Tutsis and Hutu moderates were massacred.
According to French investigating judge Jean-Louis Bruguiere, Mr Ruzigana testified that he was a member of a secret group known as the "Commando Network" which was involved in the plot allegedly hatched by President Kagame to shoot down the plane.
But the French newspaper now says it has seen a letter written by Mr Ruzigana to the judge, after he had given his evidence, which says he knew nothing about the "Commando Network".
The newspaper quotes French legal sources as suggesting that Mr Ruzigana had received "threats" to withdraw his testimony.
Mr Kagame told the BBC his decision to break diplomatic ties was to show Rwanda would not be intimidated.
"We have to stand up to this bullying that has been going on for a long time by the French against Rwanda," Mr Kagame told the BBC's Network Africa programme at the start of a four-day trip to the UK.
"Nobody has a right to fabricate stories and incriminate people," he said.
He also said the judge should instead investigate France's role in the genocide.
French institutions, including schools, were closed and Radio France Internationale (RFI) was taken off the air in the country.
Judge Bruguiere last month said Mr Kagame should stand trial at the UN International Criminal Tribunal for Rwanda on charges of shooting down the plane carrying Habyarimana.
The AFP news agency reports that a judge in a trial at the ICTR has ruled that Judge Bruguiere's report can be admitted as part of the defence case in the trial of Theoneste Bagosora, accused of being the mastermind of the genocide.
Under French law, Mr Kagame has immunity from prosecution as head of state, so Judge Bruguiere only issued arrest warrants for nine of his top aides - including armed forces chief James Kabarebe and army chief-of-staff Charles Kayonga.
French legal authorities are investigating Habyarimana's death because his aircraft had a French crew.
The judge said that only Mr Kagame's then rebel Rwandan Patriotic Front (RPF) had missiles capable of shooting down the plane.
Mr Kagame has denied this.
Shortly after Habyarimana's death, Hutu extremists started killing ethnic Tutsis and moderate Hutus, accusing the largely Tutsi-dominated RPF of the assassination.
The RPF has always said the Hutu extremists killed Habyarimana to provide a pretext to start the long-planned genocide.
The killings ended 100 days later when the RPF took power.
Mr Kagame has always accused France of backing the Hutu extremists, known as the Interahamwe.
"If there is a judge, a credible judge... [he] should be asking the role of the French in the genocide," he said.