PARIS -- An Al-Jazeera journalist will face court for illegally flying a drone in Paris, amid a spate of drone flyovers that have confounded French authorities amid heightened security concerns.

The Paris prosecutor's office says three journalists for Qatar-based broadcaster Al-Jazeera were released Thursday, a day after they were detained. Al-Jazeera said the reporters for the network's English channel were filming a report on the recent, unexplained sightings of drones over the city.

Prosecutor's office spokeswoman Agnes Thibault-Lecuivre says the journalist who is accused of operating the drone is to face court next week. Flying drones without a license in France is illegal and carries a maximum one-year prison sentence and a 75,000 euros ($85,000) fine.

Drones were spotted over the Eiffel Tower and key Paris landmarks this week, the latest of several seen around France recently.

The drone operator or operators remain at large. Officials have said they don't pose a security risk, but the flights are embarrassing and worrying for the security services, on high alert after deadly terrorist attacks last month on a kosher market and newspaper Charlie Hebdo.

Al-Jazeera said in a statement Thursday that its crew was "attempting to illustrate a piece to camera on domestic drones which are widely available, while also attempting to cover the recent drone mysteries in Paris and wider security concerns in France."

The network did not identify the journalists.

Adam Schreck in Dubai contributed to this report.