Were skirmishers deployed in front of the main armies? Or were entire armies formed out of skirmishers?
/u/elos gives a broad overview of Austro-Prussian and Franco-Prussian War tactics here. It should also be noted that due to the short time frames between these two wars, the Prussian use of skirmisher lines that he talks about in the Austro-Prussian War are quite applicable to the Franco-Prussian War.