While Cache tends to baffle and/or annoy people, I can't claim to have any new or great insights into the story.
I have just now seen it, but I am familiar with all the discussion it has provoked over the years and now I see why.
To me; it's a very simple story about two things in particular:
a) French guilt over its treatment of its Arab population historically
b) the new generation's desire to dig up and confront their "fathers" with this history
The heavy handed symbolism is in our faces trying to disguise itself under the cover of mystery and missing pieces. The one thing I felt from beginning to end is that we were missing essential pieces (scenes) of the story. Like the movie was skipping past pivotal moments. And it was.
So what happened?
Georges and Majid spent time as children together.
Georges parents wanted to adopt Majid after his parents were murdered by the French Police in 61.
Georges resented his parents' affections for Majid and plotted to destroy that relationship. The truth of how he did this and what really happened doesn't matter. All we need know is that it was bad enough to make Georges parents banish Majid from their home and lives.
Fast forward thirty odd years.
Majid has a son and they live working class lives in a crummy flat.
One day, Majid sees Georges on television and it brings it all back. He tells his son about the life he could have had and how this man on television took it away.
Meanwhile, Georges has his own family. On the outset all seems well. Everyone is happy. But Georges is either deluded or lying to himself. His wife is most likely having an affair with his friend. And his son is discontent with his life.
Majid's son and Georges son meet. How, when and where is open to interpretation and speculation - through swim practice maybe? - but their knowing each other is clearly revealed at the end of the movie. That exchange between them on the school steps is "hidden" from the audience so it is not immediately obvious that we are seeing "the explanation" revealed.
Together the two sons plot a way to draw their father's into confrontation and possibly reconciliation. I believe they had good intentions as the younger generations tend to have early on.
But, alas, this is not what happens. Older generations are stuck in their ways.
The two boys agree to record their own homes.
Part of me questions as to whether or not Majid was receiving tapes himself of his own home - while this is total conjecture, it is plausible - hence why there is a camera set-up in his own home.
What happens for both sons is not what they were prepared for.
Through the recordings of his own house, Georges' son witnesses his Mother and Pierre together (perhaps Pierre coming over for some afternoon nookie?) and this drives him into anger with her, leading to his "disappearance." He loses focus on his father and it transfers instead to his mother.
Meanwhile, Majid's son is hoping that by driving Georges to his father's home that it will in some way give Majid a catharsis - a chance to tell Georges personally all the things he has only been so far able to express to his son. But Majid is too meek and surprised by Georges arrival to be able to really express his feelings.
As with Georges son's attempts to use these videos to stir up the past and direct his father towards reconciliation, it doesn't work out that way. Instead, Georges' behaviour and anger towards Majid only opens old wounds further, and deeper.
The well-meaning naivety of the two sons trying to "help" or "change" their fathers' attitudes/relationships go very sour indeed.
Majid kills himself over the "harassment" from a "harassed" Georges. Georges has learnt nothing from his experiences.
The plan has failed.
Now both sons are themselves in denial about the part they have played in this tragedy. They have made the same mistakes of their fathers in a way.
This WHOLE EXPLANATION is symbolic for the bloody history between French bourgeois and Arab working class. Arab culture is suiciding itself in the face of French denial and arrogance.
The younger generation is trying to confront the past and heal these old wounds but they end up causing more damage because the older generation cannot and will not change.
A fatalistic view of the material, but to me, this makes sense. Maybe there's details that people have seen that challenges this interpretation.
As far as I'm concerned the final shot is telling us the answer both metaphorically and literally. If only we could "see it" through the crowd of other details.