TATP, or triacetone triperoxide, is an improvised explosive that also was used in the 2005 London bombings that killed 52 commuters.
The US government's National Counterterrorism Center lists TATP as a common explosive and describes it as "relatively easy to synthesize." Experts have said that tracing the materials used to make the explosive can be difficult because they are so readily available in stores.
It says TATP "can be very unstable and sensitive to heat, shock, and friction."
The explosive also was used by Richard Reid, who tried unsuccessfully to detonate a bomb in his shoe during a trans-Atlantic flight in 2001.
All eight of the Paris attackers died, seven in suicide bombings.
Three suicide bombs targeted spots around the Stade de France stadium, where French President Francois Hollande was watching a France-Germany soccer match. Another attacker detonated a suicide bomb on Boulevard Voltaire, near the Bataclan music hall where dozens of people were killed by gunmen, the prosecutor's office said.
