French police will track down and arrest the operators of drone aircraft seen flying illegally on several nights over sensitive sites in Paris and above nuclear power plants, a government spokesman has said.
"We need to be very vigilant on this, we're going to have to be extremely careful," Stephane Le Foll told France Info radio on Wednesday.
"The day that we find the people who are doing this, there will be penalties ... We will find them, sooner or later."
On Tuesday, police received at least 10 reports of drone flights.
In one incident in eastern Paris, witnesses saw three men retrieve the aircraft and drive off in a black car before officers could arrest them, a police source said.
Earlier on Tuesday, Interior Minister Bernard Cazeneuve told parliament that about 60 drone flights over Paris and over nuclear power plants had been reported since October 5.
Cazeneuve said he wanted to equip police with "new legal tools" to crack down on the illegal use of drones in sensitive areas.
Flights over Paris without authorisation from aviation authorities are illegal, as is the use of airspace up to 1,000 metres above a nuclear site.