This medal is what the French call "Médaille commémorative” i.e., medal given to every participant of a particular campaign or war. However, it may be a clue as to the existence of a pension, that is, a trace in the records. For a long time the medal was given without accompanying paper certificate. I am not sure about the rules of attribution for this war; however, after one loses a war, this kind of decoration are given long after the battles has ended as recognition or "thanks" and a possible pension (such was the case with the Napoleonic wars veterans!).
Regrettably, the Mémoire des Hommes official site (www.memoiredeshommes.sga.defense.gouv.fr/
) in Paris, is not covering the Franco-Prussian war. Specialized history war associations exist that could help you. If your ancestor was not an officer, i.e., not in the rolls at the Vincennes Army archives, inquire at his place of birth.
As I note the name KLEE, I suspect the soldier was from Alsace or Loraine and, like so many, may have left the motherland after the German took over. For location of possible places of birth, visit geneanet.com and do some statistics for probable birth locations listing the name. Reading French as well as German would be most helpful when digging into the Alsatian records but the Geneanet site is multilingual.