Paris authorities arrested three Al Jazeera journalists Wednesday for flying a drone in a park in the western part of the city. 

The drones were spotted near the Place de la Concorde, Les Invalides and the Eiffel Tower between 11 p.m. Tuesday and 2 a.m. Wednesday as well as over the Iron Lady and the U.S. embassy Monday night, according to USA Today. A drone was spotted Wednesday afternoon over a park in western Paris, and police arrested the three unnamed journalists. It is unknown if this drone incident is related to the night time sightings. 

Al Jazeera said the journalists were not flying the drones, but were filming it. It is illegal to fly drones in France without a license. If charged, the journalists could get a one-year maximum prison sentence and a $85,000 fine. 

The latest drone appearances follow a series of sightings in the country at French atomic plants last year and earlier this year over the presidential palace and a bay in Brittany that is home to nuclear submarines, ABC Online reported. Authorities received a call in October from the state-run power company EDF after they saw some drones over several atomic plants. 

French law prohibits small civilian drones from flying over nuclear power plants. The plants are protected by a no-fly zone that spans a 2.5 kilometer radius and a height of 1,000 meters. France has launched a $1.4 million program to detect drones because they have faced some challenges detecting the drones and operators. 

The drones are harmless, said criminologist Christophe Naudin who specializes in aerial security, USA Today said. But many Parisians are still uneasy after the deadly terrorist attacks in Paris that left 17 dead, including 12 at the offices of the satirical newspaper Charlie Hebdo. Naudin believes the goal of the drones were to instill fear into the citizens of Paris.