Police in Paris are looking to buy drones to carry out crowd surveillance, according to a tender released by the prefecture last month. The document shows that police are seeking to acquire hexacopter drones to carry out "low altitude aerial surveillance" on outdoor crowds, presumably in an effort to tighten security ahead of the UEFA Euro 2016 soccer championship, which begins in June, and the Tour de France in July.

France has been under a state of emergency since the November 13th terrorist attacks in Paris, and the government is seeking to extend it through the Euro 2016 tournament, which will be held in France. The state of emergency gives French security broad powers to conduct house raids and searches without a warrant. It was extended for an additional three months in February, despite protests from civil liberties groups who say the laws have been used to unfairly target French Muslims.

"We must avoid mass surveillance systems."

The tender published last month does not include a precise number of drones, though French media outlets have reported that police are seeking to acquire two. According to the brief, the unpiloted aerial vehicles (UAVs) must have a minimum speed of about 22 miles per hour, and must be equipped with high-definition cameras with infrared thermal imaging capabilities. The six-propeller drones must also be able to recognize license plates from a distance of at least 50 meters (164 feet) and an altitude of 30 meters (98 feet), and would fly at an altitude of up to 100 meters (328 feet). French newspaper Le Figaro reports that police plan to spend €429,600 ($486,000) on the UAVs.

Police have not commented on how they plan to use the drones, but news of the tender has already raised concerns among rights groups. "Drones can certainly be useful in very specific circumstances," Maryse Artiguelong of the French Human Rights League tells Le Parisien. "But we must avoid mass surveillance systems." A law that went into effect this year requires surveillance drone operators to inform people that they are being watched.

"In any case, what seems essential to us is that monitored people are informed," Artiguelong said.