The military ceremony Wednesday was meant to signal a fresh start in the African country but ended with the death of a suspected former rebel as witnesses along the street nodded in approval, the Washington Post reported.
"We think it was okay that the soldiers killed him," said Junior Mazongo, an employee at a tire repair shop. "In Africa, you take my eye, and I will take yours. You take my arm, and I will take yours."
The soldiers took tires from the shop, put them on the corpse and set the pyre afire before posing for pictures in front of the burning body, the Post said.
Since the Seleka rebels seized power in a military coup in March, thousands of civilians have been killed or displaced as mostly Muslim rebels and Christian militias clashed in the Christian-majority nation. Last month, rebel-installed President Michel Djotodia resigned as a result of pressure from other countries in the region and Catherine Samba-Panza was named interim president.
During the ceremony Samba-Panza pledged to secure most of the country "within a month" and vowed to punish anyone who promotes instability.
"At a certain point, everyone will be held responsible for their acts," she said. "I am warning troublemakers who continue to sow disorder in the country."
The attack on the man occurred after she left, the Post said.
Peter Bouckaert, emergencies director for Human Rights Watch, told the Post he arrived soon after the man was killed. He said African peacekeepers were present but did nothing. French soldiers arriving later cleared people away.
"The body was completely on fire," Bouckaert said. "People were taking photos, kids were standing around watching. The French troops walked up to the body and told people to back away."
Bouckaert said it was essential for Samba-Panza to condemn this "act of barbarity" and ensure soldiers -- who can be identified in the photo -- are held accountable.
"This was a beautiful moment this morning," Bouckaert said. "It was a moment of hope that suddenly turned into a moment of absolute horror once again."