Back pay is a start but until HR people go to gaol for illegal employment practices then it will not stop.

I'd be surprised if HR knew. A manager could easily change what he was doing on a daily basis without HR being any the wiser.

Yes but wouldn't HR have been doing the recruiting or at least the paperwork to get the person through the door for security. If a manager appointed someone as an intern they would still have to notify HR for insurance purposes.

My point is that if a manager hired him as an intern, once he was in the door with all the HR paperwork done, he could get him to any other work without telling HR.

In which case the HR manger should refer the manager to the police once it goes ballistic. If your manager did something illegal then they should suffer the consequences. HR should only avoid prosecution if someone fails to inform them and breaks the law.

An intern is an intern over here. They do the work to see if it is for them and the employer looks at what the person does, to decide if they fit in. They can end up doing almost anything that is related to the type of work they are 'applying' for. Although 3 months is long, compared to here, generally it is one to 2 weeks over here.

Here the interns are supposed to be trained. If it is of benefit to the employer then they need to be paying minimum wages at least. If it is just to see how a person fits in then that is not an excuse here as they can fire someone without cause within two years anyway. So if a person did not fit in then they can be fired without cause or risk of tribunal. I have heard of people doing six months internships or multiple internships with different employers before they get a paid job. I am not sure of the ability of employers in Germany to get rid of people is so maybe short internships are practical. Though much of the time it ends up as free labour for the company.

Here, people will often take a weeks leave from their current employer and go to another company to see if they fit in.