Apparently shooting in Croatia
Found some news about it:
"A helicopter with members of the US Special Forces hovers above the lake in search of treasure at the bottom ....
Part of this is the story of the American film ' The Lake 'A production whose staff these days recorded in Lokve in Gorski Kotar. The budget of the film is around 40 million."
http://dnevnik.hr/showbuzz/celebrity/pocelo-je-snimanje-akcijskih-scena-filma-the-lake-slavnog-luca-besssona-u-lokvama---386966.html