At least five drones were spotted early Tuesday, while it was still dark, flying over landmarks in Paris, the BBC reports.
The unmanned planes were first seen flying near to the US Embassy, and later over Place de la Concorde, the Eiffel Tower, and near the Invalides museum and Bastille.
The map above shows where the drones were seen after midnight.
"It could be a coordinated action but we don't know for now,"a source told the AFP.
Lots of people use drones to take footage of well-known landmarks, but the number of drones in one night has raised concerns, especially after the Charlie Hebdo terrorist attacks.
In France, it's legal to fly drones in France during the day, but it's banned during the night. Le Monde reports that anyone found flying a drone at night in France could face up to a year in prison and a fine of up to €75,000 (£54,882).
Experts told the AFP that the drones were too small to cause any serious damage. Investigators are still looking for the drone operators.