Gabriel Guevara was arrested at the Venice Film Festival this weekend -- but not for anything he allegedly did while there ... it actually stems from something in another country.
The Spanish actor -- famous for a starring role in a new Amazon movie -- got taken into custody by the local authorities Saturday while he was in Venice ... this after an international warrant for his arrest was issued out of France on a sexual assault charge.
The details of the alleged incident have yet to be released -- and the extradition process might take a while too ... as a court of appeals reportedly has to weigh in first.
Guevara was actually set to receive a pretty big award on Sunday -- the day before he was busted -- from the Filming Italy org ... which was going to honor him as the "Best Young Actor." Upon hearing about his arrest, they scrapped that entirely ... and put it on hold.