A quarter of a century since he fled the central African country, Habre's hearing in front of the Extraordinary African Chambers got underway on Monday.
Habre, clad all in white, was brought into the courtroom and seated in front of the judges' dais before the media were allowed to enter. A source close to the special court told Reuters he was brought in "by force."
The legislative body was set up by Senegal and the African Union in February 2013 to prosecute the "person or persons" most responsible for international crimes committed in Chad during Habre's rule between 1982 and 1990.
Human Rights Watch lawyer Reed Brody said the "African Union saw the importance of being able to show that you can have justice in Africa."
HRW claims to have obtained evidence proving that Habre's regime oversaw the torture or murder of some 40,000 people during his eight-year reign. Among the victims were opponents and rival ethnic groups which Habre deemed a threat to his stranglehold on the nation.
Crimes against humanity
Once dubbed "Africa's Pinochet," the 72-year-old has been in custody in Senegal since his arrest in June 2013. During his pre-trial custody, four investigating judges spent 19 months interviewing some 2,500 witnesses and victims and analyzing thousands of documents.
Habre was also wanted for trial in Belgium on war crimes and crimes against humanity charges after three Belgian nationals of Chadian origin filed a suit in 2000 for arbitrary arrest, mass murder and torture.
Macky Sall, Wade's successor who took office in April 2012, ruled out Habre's extradition to Belgium, however, and instead vowed to organize a trial in Senegal.
Habre's case is the first anywhere in the world where the courts of one country are prosecuting the former leader of another for alleged human rights crimes.
The historic case will also be the first time that the concept of "universal jurisdiction," which allows a suspect to be prosecuted for their past crimes wherever they are in the world, has been implemented in Africa.
"There are a lot of historical aspects to this. But, for me, the most important kind of thing is that it is the survivors who have pushed for 25 years," Brody said.
Around 100 witnesses are due to give evidence during the hearings, which are expected to last around three months. Some 4,000 people have been registered as victims in the case.
Habre, however, has said he does not recognize the court's jurisdiction, and has vowed that he and his lawyers will play no part in the trial. Under Senegalese law, however, he could still be forced to attend.
ksb/kms (AFP, epd)