The two men and one woman were part of a group of five who were reportedly drunk when they went down into Paris’ famous catacombs on Monday evening.
The group became separated with two managing to find their way out. The remaining three, all in their early 20s, were not so fortunate and spent two more days trying to find their way out.
The catacombs in the south of Paris were opened in the late 18th century and hold the remains of an estimated 6 million people.
Thousands of tourists visit certain sections of the tunnels where the skulls and bones of the dead are often arranged into artful or ghoulish displays. There are secret entrances to other parts of the underground network all over the city.
The alarm was not raised until Wednesday at which point 35 police officers went down into the tunnels to look for them.
“At that depth, no telephone network or radio frequency works,” a police spokesman told AFP.
Police eventually came across a piece of paper left by the three which said they were lost and that they had headed towards the south of the tunnel network.
They were eventually found later in the afternoon. The three were in reasonably good health, although one was reported as being in “a state of shock.”
As further punishment, the three are likely to face a fine of up to €135 and a ban on going back into the catacombs.