According to Eurosport, the french manager is requesting an investigation aver a drone was spotted flying over their closed training session! I just wanted if its just a keen (and careless) fan trying to get some cool holiday footage, or actually some sport espionage going on! 
. The closed training sessions are usualy used to decide on game tactics and player suggestions and if I rival team does acquire this information it can possibly give them a tactical advantage. Since France and Switzerland are both in group E, maybe the Swiss hired team black sheep to help them out 
The tweet below shows the incident on the news!
https://twitter.com/OfFzh/status/476480857767940096/photo/1
On another note, it seems that some teams are actually using quadcopters for training analysis to improve the teams training and performance. The video below shows how drones are not only being used in sports for cool shots!
