After WWI, a variety of German veteran organization sprang up across the country, keeping with a long-established tradition.  One of these was the "Kyffhäuserbund" (Kyffhäuser Veteran's Organization) who issued a brass type oval medal to commemorate service in WWI.  For many veterans, this was the only WWI service medal that was worn until the German Cross of Honor ("Ehrenkreuz") was officially established in 1934.   After the Cross of Honor was authorized, many veterans continued wearing their unofficial medals so it is not uncommon to find this with an official medal grouping - usually worn on civilian clothes, band uniforms, etc.  Obviously, if they were wearing their medals in official uniform, the medal wasn't allowed.   It's interesting to note that many - if not most - of the organizations allowed veterans of the 1870-71 Franco-Prussian War to join - normally as honorary members - and allowed them to wear the organization's medals.  On 2 May 1931, possibly the last Franco-Prussian War veteran joined.  In this case, the following guides may be of interest:   http://reviews.ebay.com/1870-71-Franco-Prussian-War-Medal-Unofficial-Clasps_W0QQugidZ10000000003196397, http://reviews.ebay.com/1870-1871-Franco-Prussian-War-Medal-clasps_W0QQugidZ10000000002349162, and http://reviews.ebay.com/Prussian-1897-Centenary-Medal_W0QQugidZ10000000002369985.  The main trivia point being that a Kyffhäuserbund Medal with a Franco-Prussian War Medal and 1897 Centenary Medal is unusual but certainly not impossible and does not indicate service in WWI. 

  Examples mounted in contemporary groups

This very low cost medal is fairly well documented and illustrated on the internet.  What generally isn't illustrated is the numerous devices or attachments that might be found with it but not necessarily.  Since the veteran had to purchase the medal (often included in the initial membership fee), finances sometimes prevented buying every (or any!) device authorized.  Each organization had a list of devices available and the veteran could make his own selection from that list, at an additional cost.  The most common device found is the crossed swords (which indicate a combatant).  Absence of the crossed swords does not necessarily mean that the recipient was a non-combatant, just that they are not on the ribbon.  The medal is sometimes found with a laurel wreath supporting a diagonal sword (which usually indicates a naval combatant recipient - but it was the buyers decision).  Other attachments are the various battle bars which closely resemble those found on the Franco-Prussian War Medal.  Probably the most common is one that has "PARIS" (probably followed at a distant second by "YPRES") in black letters on the bar which is roughly the size of the ribbon width to almost doubled the size (depending on manufacturer).  Other battle bars are available and have almost every German battle listed.  The most bars I've seen attached to one medal was 7 but this one appeared to be a "made-up" grouping of bars.  The rarest bars would possibly be ones for Africa (no originals are currently known).  I've never seen a "country" bar - only battle associated.  All devices and attachments are generally made of a similar metal as the medal but come in a wide variety of sizes and styles (depending on the manufacturer).  The impressed names on the bars are usually filled in with black enamel.  Most devices use a double prong back attachment although one series of the battle bars are the "slide-on" type and are large enough for a double-wrap ribbon. 

Forgery of this very common medal is usually not a problem due to its' very low cost.  It would cost as much to copy it as the original is worth.  About the only economical method of making a copy of this medal is making cast copies of it and then painting it - which is readily detectable and the cost would still come very close to the price for an original. 

This particular guide will be updated more often than my others because a lot of detailed information is available but it's difficult to readily locate.  Please visit my other guides and blog (http://blogs.ebay.com/tsa-li) for further information.