If you had to guess which movie director was recently the first to be granted access to the nonpublic areas of the catacombs six stories beneath the streets of Paris, you might say, Luc Besson, Leos Carax or another of France’s most prominent names.

Mais non. That honor has gone to John Erick Dowdle and Drew Dowdle, Minnesota filmmaking brothers who have made a name for themselves in Hollywood with smartly scary indie horror films like “Quarantine” and “Devil.”

Opening Friday, their new film “As Above, So Below” follows two young archaeologists (Perdita Weeks in the lead role and Ben Feldman, best known as the troubled Ginsberg on “Mad Men”) as they and a claustrophobic cameraman (Edwin Hodge) pursue a fabled philosopher’s stone said to be buried deep in the uncharted catacombs.

Along the way they discover secrets that cause them to examine their own personal demons, hence the movie’s title.

Getting permission to shoot wasn’t easy. “We had to jump through a lot of hoops, but it was more a matter of cutting through bureaucracy than resistance,” said John, 41, the directing half of the duo.

That hurdle turned out to be minor compared with what was to come. Shooting hundreds of feet underground in dank pitch-black tunnels with cameras and lights strapped to their foreheads presented their biggest logistical challenges to date.

“We’d be up to our chests in water, with just a little access to air, having to keep everyone in the crew calm,” he said. “Ten hours a day down there, you’d start to feel a little loopy. The walkie-talkies and wireless didn’t work because the walls were too thick, so every scene it would be the actor, then the sound guy, then us all running through spaces with our head lamps turned off. We’d really take a hit where the ceiling dipped lower. Our camera guy was wearing a head brace by the end.”

The psychological effects were also notable, said Drew, 40, the film’s producer, who also cowrote the screenplay with his brother.

“On our first location scouts, we went in with the sound system, crawling on our elbows and knees for 50 yards at a time through these holes in the ground,” he said. “About four hours in, when we were like a mile deep, one member of the crew had a full-on meltdown. We thought, ‘Wow, this space really works. We need to repackage that.’?”

Despite the complete saturation of the horror genre, the brothers are confident that an original, intriguing horror film is still not impossible to pull off.

“We just try to think of what would get us to go see a movie,” John said. “Plus, this one is really an Indiana Jones-type adventure, but with a female lead, that leads into a horror space: something epic in scale, done in a personal, intimate setting, that gets the audience invested in the search.”