If I correctly guessed what you are talking about (https://en.wikipedia.org/wiki/Federal_Department_for_Media_Harmful_to_Young_Persons#The_indexing_process http

If I correctly guessed what you are talking about (https://en.wikipedia.org/wiki/Federal_Department_for_Media_Harmful_to_Young_Persons#The_indexing_process https://en.wikipedia.org/wiki/Federal_Department_for_Media_H...) then yes, it's about advertising. That law is about protecting minors from getting in contact with material that is deemed highly dangerous for them (e.g. the game "Manhunt" is on that list). Just telling them in the search results might be enough for them to seek out this game and eventually get it. Edit: The law actually clearly states that a shop must not have the game on display anywhere a minor could see it You are by the way the way totally allowed to sell these games. Without any advertising that is. In a classic shop that meant you keep it under the counter and if someone over 18 asks for it by name, you sell it. No idea how that would translate to an online shop. But long story short: It seems very hard to interpret returning 451 to a url the user already has to know in advance as advertising. I am pretty sure that if a minor asks for that game in a store you are also allowed to say "no, you are too young for this" and are not required to lie "what, no, never heard of that" ^^.