Nicknamed "Mr. Z", Zigiranyirazo is the brother of Agathe Kanziga, widow of the former Rwandan President Juvénal Habyarimana, killed in the attack against his plane on 6 April 1994.
The first instance judges found him guilty of genocide and extermination after having concluded that he had helped and encouraged the massacres of ethnic Tutsis in his native prefecture of Gisenyi, northern Rwanda, and around his residence in the capital, Kigali.
His action resulted in the death of more than 1,500 people, according to the court.
According to the ICTR website, "Mr Z" will appear before a Chamber presided by the American Theodor Meron.
As in first instance trial, he will be defended by Canadian lawyers, John Philpot and Peter Zaduk.
Habyarimana's brother-in-law was arrested in Belgium on 26 June 2001 and was transferred to the ICTR detention centre on 3 October of the same year.
© Hirondelle News Agency