Leon Mugesera, an academic, was extradited back to his home country from Canada four years ago.
He made his incendiary speech against the Tutsi minority in 1992. Some 800,000 people died in the genocide.
Mugesera later worked as a lecturer in Quebec province and lost a 12-year legal battle to avoid extradition.
In 1992, then an official in Rwanda's ruling Hutu party, Mugesera  told more than 1,000 party members that they should kill Tutsis and dump their bodies in the river.
Mugesera later maintained his innocence, saying the speech had been taken out of context.
The genocide ended when rebels, led by current Tutsi President Paul Kagame, seized power in July 1994.
Militias from the majority Hutu ethnic group were blamed for the mass slaughter.

12 March 2016 Last updated at 08:26 GMT
One of the bears went over to check out the strange object, giving it a quick sniff, before being joined by two others.
The bears batted it around until their sharp claws eventually popped it.
Xaviera Simons was visiting the safari park when she filmed the moment.

Gordon Culliford, 77, from Ammanford, Carmarthenshire, was last seen at about 13.15 BST on Thursday at the city's Singleton Hospital.
He is white, 5ft 7in tall, with white swept back hair and was last seen wearing black glasses and a red jacket.
South Wales Police said there is "considerable concern" for the man and called or information.

A spending timeline until 2022 shows the price could be about £435,000 more than approved in the Scottish Borders authority's budget earlier this month.
The Scottish government contribution to the project has been estimated at about £32.5m.
The council is being asked to approve the final outline design of the scheme and aim to publish it in April.
A report to the local authority described publication as "the most important stage of the project for determining the programme and successfully obtaining funding".
It warned that if the objection resolution process went beyond an estimate of three months, it could put funding at risk as well as the delivery target of June 2021.
However, the project team has tried to avoid that prospect with extensive consultation over the past two years.
A former politician who described Tutsis as "cockroaches" and called for their extermination has been jailed for life in Rwanda over the 1994 genocide.
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