So the overtime and "on call" is not regulated on the country level?
In Poland it is, we have limits of how much overtime one can have, how much money you get when working overtime (e.g. during the week it is +50% more per hour, during the weekend it is +100% more).
One has to have at least I think 11 hours of free time from work ("on call" + usual office time hours) per 24hrs during the week and it is 36 hrs during the weekend.
Some things are regulated in the law (Angestelltengesetz), some parts are regulated in "collective contracts" (Kollektivvertrag), some parts are in a company wide contracts (Betriebsvereinbarung), and then there is your individual contract.
In Poland it is, we have limits of how much overtime one can have, how much money you get when working overtime (e.g. during the week it is +50% more per hour, during the weekend it is +100% more). One has to have at least I think 11 hours of free time from work ("on call" + usual office time hours) per 24hrs during the week and it is 36 hrs during the weekend.