Sounds like a good way to end up in jail.
There's nothing legally stopping me from publishing all of that data, or selling it on the side. At least not to my knowledge.
Just think... there's at least one of someone like me at every service you use on the Internet.
I seriously doubt that publishing people's private info you got from your company would be legal based on European privacy laws (regardless what your company chose to have you personally sign).
I imagine going to jail is unlikely in any case. And I doubt it would be connected to your employment contract in any case: jail would likely be the result of some criminal offense you committed against the state, not against your employer.