Don't larger companies in Germany usually do flex-time (Gleitzeit) for non-management employees?

So, my boss can require that I work an extra 10 hours this week, but I need to get it back at some point, right?

I know it as "Zeitausgleich". You don't get paid overtime but you accumulate time off. Pretty much like getting additional vacation days. And to be honest, I kind of like this system. I'm happy to work >40h every now and then, but I won't work >40h on average.