PARIS (AP) — French lawmakers leading an investigation into the Nov. 13 attacks and the first responders at the Bataclan concert hall that night are returning to reenact the horror that left a total of 130 people dead across Paris.

Thursday's exercise is intended to shed light on what happened when three gunmen claiming allegiance to the Islamic State group opened fire during a packed rock show. The metal gate of the Bataclan opened briefly to allow two dozen people inside.

The investigation is intended to help France avoid a repeat of the attacks but some victims' families have criticized the exercise as needlessly painful.

Later in the day officials will stage a fake bombing on a mock sports crowd reminiscent of the suicide attacks on the French national stadium outside Paris.