He probably only arrived at 12:00 and is complaining about everyone that has a live besides work (children, hobbies, volunteer jobs etc) and arrive early.
Considering there's laws in Germany that prevents you from working more than 8 hours a day, hes either in violation of those laws or full of shit.
It's pretty much true for any office worker. They can stay up to 10 hours a day, but only if their average day isn't longer than 8 hours in a period of 6 months.
Vacation and illness don't count as a counter measure.
Pretty much everything else has to be approved by government entities.
Maybe he can stay longer, but if he's the boss he's even more full of shit if he demands them to break the law, because it is his responsibility to keep track and make sure nobody is working any longer than that.