Mysterious Drone Flights Over Paris Prompt Curiosity and Concern

— -- PARIS -- As night draws in over Europe, Parisians are wondering if the mysterious drones will make another appearance in the skies over their city tonight.

For the past two nights, the pilotless aircraft were sighted over key Parisian landmarks. On Monday, five drones were sighted near the Eifel Tower, close to the Place de Concorde and over the U.S. Embassy, local officials said. Last night the drones appeared again between 11 p.m. and 2 a.m., though this time only three were sighted flying over central Paris.

So, what’s the explanation for this "mystere," as the French call it? Is it something sinister or just a few enthusiasts having fun?

“Right now there is no worry to have but we should be vigilant,” the French government spokesperson Stephane Le Foll said on Wednesday.

Whoever is flying these drones are breaking the law. Flying drones over Paris is strictly illegal at night, even with a license.

Drone racing is becoming an increasingly popular pastime in France. Journalist and drone racer Laurent Khong told ABC News that whoever is flying the night time drones is doing enthusiasts a big disservice because it gives people the impression that drones are dangerous, "and then we don’t get the licenses we need to do our races,” he said.

Khong said he believes it is “probably tourists,” because the sites involved were all tourist attractions.

A more sinister explanation is offered by criminologist Christophe Naudin, who told the French newspaper Le Figaro, “We are probably dealing with a well-structured and financed organization. Maybe eco-terrorists.”

What to do about the drone flights is another point of disagreement.

Mohammed Douhane from a French police union suggests a number of options. Taking them "out" with a bigger drone -- which would be dangerous over a built-up area -- or capturing them in a net attached to another drone. Or the option "favored by the government at the moment to track down these drones so they can reach the owner, arrest and, of course, take him to the law."

Of course, it's unlikely they’ll be caught if they don’t fly again but tonight many Parisians have their eyes raised to the skies on the chance they’ll get another sighting.