Here's everything we know about the mysterious Paris drones

This isn't just a puzzle - it's also illegal. Flying unmanned aerial vehicles (UAVs) over urban areas at night in France is strictly forbidden.

If found, the pilots could face €75,000 fines and a year behind bars. But right now, no one has any idea who they are.

So what do we know?

• There's been two consecutive nights of flights. On Monday and Tuesday night, drones were spotted hovering above famous French landmarks.
• Sites targeted by the drones include the Eiffel Tower, the Place de la Concorde, the US Embassy, the Invalides museum, the Bastille, and the old city gates.
• There's almost certainly more than one drone. The time period over which they were sighted (between 11 p.m. and 2 p.m. on Tuesday, for example) and the distance between sites suggests the use of multiple drones.
• Authorities are not concerned about a security risk. "There is nothing to worry about," a spokesperson told reporters.
• Three Al Jazeera journalists were arrested after operating a drone in order to produce a news segment on the drone mystery. Two have since been released, but another is facing court next week.
• The US Secret Service is now getting involved. According to a CNN report on Wednesday, the US Secret Service is "consulting" with Parisian authorities over the mystery. The American Embassy was one the location of one of the incidents, after all.
• There's footage of the drones. The BBC reports that there's a 10-man team analysing footage captured of the drones on Tuesday night. It might offer up clues as to their purpose, whether that's cameras or payloads.
• A Reddit user was looking for drone pilots in Paris last month. It could be unrelated, however. (We've reached out to the user for clarification.)
• Drones have previously been spotted flying near French nuclear power plants. The Independent says a "campaign by anti-nuclear campaigners" is the most likely explanation, and there's not yet any indication if they're linked to the mystery drones presently in Paris.
• The most likely explanation is hobbyists. Drones are increasingly popular purchases, and can capture stunning aerial footage when equipped with cameras. It's possible that the sightings were drone photographers who didn't know - or didn't care - about French law.

A few drones flying around doesn't necessarily sound like a particularly worrisome event, even if it is illegal. But it's important to remember that this come just weeks after more than a dozen people were killed in shootings at the offices of satirical magazine Charlie Hebdo and elsewhere. Understandably, tensions in Paris are running high.

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