Gbagbo appeared Tuesday before the International Criminal Court for his confirmation of charges hearing. He's accused of crimes against humanity in post-election violence that gripped Ivory Coast following 2010 elections.
ICC Chief Prosecutor Fatou Bensouda said the elections were meant to unite an Ivory Coast divided by civil war but instead sparked "unspeakable violence."
Gbagbo stands accused for four counts of crimes against humanity.
"The prosecution's evidence will show that, Mr. Gbagbo and members of his inner circle adopted a policy and common plan with the objective of maintaining Mr. Gbagbo as president of Ivory Coast by any means, including by lethal force," Bensouda said in opening statements.
Gbagbo was transferred to The Hague following his 2011 arrest.
Gbagbo's arrest secured Alassane Outarra's claim to the presidency. Rights group accuse both sides of committing atrocities in the post-election violence.
"If all the perpetrators are not prosecuted and impunity prevails in Ivory Coast, there is a great risk that the preventative effect of justice will dissolve, in detriment of present and future victims," Drissa Traore, president of the Ivorian Movement for Human Rights, said in a statement.