They don't. It is not a requirement. But if you want your employees to do overtime, you have to pay them either 50% more or 100% more, depending on whether it's

They don't. It is not a requirement. But if you want your employees to do overtime, you have to pay them either 50% more or 100% more, depending on whether it's "just" overtime or overtime during a time when they wouldn't have to work at all (weekends, official holidays, ...). The very short, very inaccurate summary is, you get 50% for outside of hours (after 19h, weekends). You get another 50% for working on weekends. And you get 50% for working on official holidays. Meaning you get 3x your normal hourly wage for working after 19h on Easter or Christmas for example. Needless to say, companies don't want to pay this, and will lie and cheat to get out from under this. Problem is, if they get sued, the maximum penalty is 2 years' wage, paid out on the spot, and it's up to the employee to decide whether to continue working there or not (if you fire an employee, and put down as reason that you've lost a court case against them, that's likely to result in another 2 years pay for the employee).