I don't do post modernism, in fact i am in Victoria doing VCE, but i studied Amelie in Media, so some of the things i covered might be relevant.
I would say that the use of filmic techniques like putting the beating heart outside her top so you can see it (when she sees Nino), and the key when she gets a copy of Collignon's key made.
Also maybe surrealist-type things like when she turns into zorro briefly after she goes into Collignon's flat for the first time and she inscribes a big Z on the door.
In terms of animating, not only the pictures in her room as someone else mentioned, but also the set of four photos that Amelie wrote on the back of for Nino, as they become animated and talk to him at one point.
Also the fact that it includes imaginary things in the film - the things she imagines on the tv such as her funeral, and also the imaginary giant green alligator that she plays with near the beginning of the film.
Also maybe that there are a lot of genres, because at points it is a comedy, at others a romance, at others a drama etc.
Possibly the constant narration strikes me as a somewhat post-modern thing.
Also i believe the fact that Amelie is a dominant female character who ultimatly succeeds in overthrowing her evil male binary opposite (collignon) and that she achieves her goal of finding love is a post-modern idea, as dominant female characters were not seen previously. (i think this is right - i studied post-modernism in relation to buffy in yr 10 and we said that of her character).
Anyways, all of this may in fact be completely useless to you, but i figured i would put it up anyway just in case!