What are the regulations governing speed when overtaking?

You answered correctly. When overtaking in Germany, three important rules must be followed: First, the overtaking vehicle must drive noticeably faster than the vehicle being overtaken—this ensures the overtaking process happens quickly and safely. Second, even while overtaking, the driver is not allowed to exceed the legal speed limit. Third, the driver who is being overtaken is not allowed to increase their speed during the maneuver. These rules together help prevent dangerous situations and ensure clear communication between drivers. Remember them whenever you are overtaking or being overtaken.