General Laurent Nkunda was a staunch ally of Rwanda
Congolese rebel chief Laurent Nkunda has gone to court seeking to end 14 months of house arrest in Rwanda.
Lawyer Stephane Bourgon told the BBC that Gen Nkunda was being illegally detained by Rwanda.
He said that he would go to the African Court of Human Rights if Rwandan judges declined to hear the case.
Gen Nkunda was at the heart of years of unrest in eastern Democratic Republic of Congo before he was surprisingly arrested by Rwanda troops last year.
An ethnic Tutsi, like Rwanda's leaders, he had been accused of protecting Rwandan interests in DR Congo by fighting Hutu militias based there.
The BBC's Geoffrey Mutagoma says hundreds of people attended the hearing at the Supreme Court in the Rwandan capital Kigali, with some people standing up.
However, our reporter points out that the Supreme Court normally deals with appeal cases and yet this is the first hearing of this case.
The court said it would decide whether it could deal with the matter on 26 March.
Another of Gen Nkunda's lawyers told the AFP news agency that they had approached the Supreme Court because a military court had refused to hear the case.
Mr Bourgon told the BBC that he would continue to seek a "non-judicial" solution, which he said would be best for everyone.
DR Congo has said it would like Gen Nkunda to be extradited on charges of war crimes.
He was arrested in North Kivu in January 2009 after DR Congo and Rwanda agreed - under intense international pressure - to work together to bring peace to their border region which has seen 15 years of conflict.
DR Congo agreed to let Rwandan forces onto its territory to tackle Hutu rebels, some of whom fled Rwanda after being involved in the 1994 genocide of Tutsis.
The UN and the Congolese army have since tried to wipe out the Hutu militias but their campaign has been hit by allegations of human rights abuses.