Prosecution lawyer Nicolas Peron said there was no evidence that Rwamucho personally carried out extrajudicial executions and torture.
But he said that the 65-year-old man should not “evade his duties” because you can “kill with words”.
Prosecutors accused Rwamuzio, who was born into a Hutu family, of spreading anti-Tutsi propaganda.
They also cited witness statements accusing him of helping bury victims in mass graves “in a last-ditch effort to destroy evidence of the genocide.”
Prosecutors asked for a 30-year prison sentence, while survivors called for a life sentence.
Angelique Uwamahora, who was 13 years old at the time of the genocide, said she saw Rwamutsio at a checkpoint in the town of Butare and heard him calling on militiamen to kill Tutsi, the Associated Press reported.
“He wanted to incite them to kill us so we wouldn’t get out alive,” she said.
But Rwamucho told the court: “I assure you that I did not order the killing of the survivors, nor did I allow them to be killed.”
His lawyers argued that his participation in mass graves was because he wanted to avoid the “health crisis” that would have occurred if they had not been buried.
They said he was being persecuted for his disagreement with the current government in Rwanda.
Light was arrested in Sannoit, north of Paris, in 2010 after attending the funeral of a former Rwandan official convicted of war crimes during the genocide.
In December, former doctor Susten Munyemana was sentenced by a French court to 24 years of imprisonment for crimes including genocide and crimes against humanity. He was accused of organizing torture and murder during the genocide.