This ^^^FargoDog said:The Vengeance Trilogy by Park Chan Wook. Korean films and absolutely stunning, if a little strange by western standards.
Let the Right One in by Thomas Alfredson. Swedish, and one of my favourite films ever, never mind solely foreign films.
See them. Now!
EDIT: Also, [REC], a spanish POV horror film remade in the US as 'Quarantine'. Far better than 'Quarantine' and extremely intense towards the end.
As each sentence flew by I wished, " Please leave one of my favorite Foreign films for me to recommend..." with no avail.
Posters below. If you haven't seen these films, you have been doing a massive disservice to yourself.