The correct time to use "Gute Nacht" in Germany is before going to bed. This is a common way of saying "good night" to wish someone a restful sleep. To find the answer, we can understand the meaning of "Gute Nacht" in German. "Gute" means "good" and "Nacht" means "night". By knowing the translation, we can determine that "Gute Nacht" is used to bid someone "good night" before they go to bed.
The correct time to use "Gute Nacht" in Germany is before going to bed.