Drones have been seen flying over tourist hot spots in Paris for the second night in a row. That has raised concerns in a city already on high alert.

Police are working to track down whoever is controlling the small unmanned aircraft that have been seen in the vicinity of the Elysee Palace, the Eiffel Tower, Place de Concorde and the American Embassy.

“We don’t know whether there are five drones or one drone seen in five locations. The timings of the sightings have not been clearly established,” explained Jean-Marc Tanguy, a journalist specialising in military issues. “It could be someone controlling these drones through a window, and if they’re in the city centre they don’t need to move to cover a big area. Now the problem is to detect where these drones are being controlled from.”

As the drone mystery deepens, experts point out that the ones seen flying over Paris landmarks are not military drones like the ones deployed over war zones like Syria and Iraq armed with bombs and m