Many militaria collectors collect WWII era German items and attempt to use ebay as a venue for their collectibles. While ebay.com specifically prohibits this, a more in-depth look at section § 86 of the German Penal Code (StGB) is provided. Please note that this is not my opinion but rather a rough translation of the German law. Here is an English summary:
§ 86. Items that are used for making propaganda for a party or group which is classed as unconstitutional or forbidden, even if they act outside Gemany, may not be spread inside Germany. This applies to items made to propagate ideas that correspond with the ideas of the "Third Reich". They might not be made, kept, imported or exported. The punishment may be prison (up to three years) and/or a fine. This does not apply if those items are used in order to inform others, repel actions that are aimed against the constitution, if they are used in art, science, research, teaching, or to report about historical events or similar purposes. If you use or show symbols or signs used by parties or groups that can be classified as unconstitutional, or if you manufacture, keep, export or import those, you may be punished (three years imprisonment and/or fine).
You may not use or spread items that display or contain those signs or symbols, e.g. flags, insignia, uniforms (or parts of uniforms), mottos and forms of greeting. You may also not use or spread signs or symbols that look similar to those. This does not apply if those items are used in order to inform others, repel actions that are aimed against the constitution, if they are used in art, science, research, teaching, or to report about historical events or similar purposes.
NOTE: This can be basically paraphrased into 2 major points with recent German Criminal Law rulings applied: 1. Contemporary and military-historical articles (especially those from National Socialism) are only for purposes concerning the civic information, the defence of unconstitutional and anti-constitutional activities, the scientific and art historical research, the information and reporting on the events of current affairs or the military-historical and uniform research and that this complies with § 86 German Penal Code (StGB) as well as with other valid laws. 2. The owner binds himself legally to these objects for historical-scientific purposes for the reasons mentioned in paragraph 1 only and will not use them in any propagandistic way in accordance with § 86 German Penal Code (StGB) or in any other criminal or anti-constitutional way.
While the law is stringent, ebay policy is determined by French legal actions - not German. Many auction sites similar to eBay offer WWII German militaria to an international market in compliance with German laws - even eBay.de handles the situation different and is much less stringent than it's American mother. If you're a legitimate militaria collector (and not a skinhead, neo-nazi, anarchist, or something similar), then there is generally no problem collecting within Germany. The one point that will strike many as strange is that you may be required to register, provide references, and/or undergo an "interview" of some sort to verify that you are a legitimate collector.
For more info and a wider discussion, please go to my blog (http://blogs.ebay.com/tsa-li) and/or guides. Thanks for viewing!