The man was arrested Tuesday evening after he jumped a barrier armed with a fire extinguisher, The Local.fr reported. Police said he appeared to be "in a drunken state," the newspaper Le Parisien said.
The Tomb of the Unknown Soldier lies beneath the arch and holds the remains of an unidentified man killed in World War I. The eternal flame was lit there in 1923 and is relit every evening at 6:30 p.m.
The man admitted he was trying to put out the flame, police said.