Bon Cop, Bad Cop.
It's a true classic. What they did was brilliant. Being a bi-lingual country, they decided to make it a bi-ligual movie, with language being part of the story, using subtitles as needed, and different depending on the English or French versions.
Here's one of my favourite scenes from it where the French guy teaches him how to swear in French. Classic.http://ca.youtube.com/watch?v=9U72QVCgh_Q