The Walther Knife is indeed good in the hand and with a little effort it can also bring on a reasonably useful sharpness, but the blade length and especially the blade geometry are definitely not §42 compliant and therefore the blade is covered by the ban on carrying in Germany. Of course, this applies to most other outdoor knives also to (the one with the length), however, has this Walther knife an almost perfectly symmetrical blade geometry, similar to a boot dagger. The upper phase of the blade is not sharpened, yet so thin that this knife is clearly a pure Engraving Tool. Thus, would also be in the forest hardly a "legal reason" reasonably plausible to explain. Hardly a police officer should get involved in this unique blade shape to a discussion. As a pure collector knife it would be ok but of course as a utility knife under any circumstances, because you can wear it simply nowhere (not even in the forest).
So who has the right to wear this knife: Stay away!