There's a pending law in Germany where it will be against the law for employers to search Facebook for potential hires.
Under a draft workplace privacy law now being looked at by the German parliament, employers would be barred from poking around the Facebook pages of job applicants, part of a broader push in that country to enact restrictions on how far employers should be permitted to pry into workers' lives. The law will also restrict employers from reading emails.
Although this seems like it will be impossible to prove the an employer did this. After all the only way you could prove is by looking at the employers browsing history and then you're infringing on the rights of the employer. Correct? It's a great idea but the fact that it's unenforceable makes it irrelevant.
The law will not ban employers from using sites like LinkedIn to research applicants. This is because they see LinkedIn as business related.