Quote Originally Posted by Conradus
This is the German view, Bismarck was only too happy to have a reason to start a war and unite the other little German states into one Reich. I'm not saying that it's only Germany's fault, but it certainly isn't only France's.
Quite aside from Napoleon III, who was probably rather ill at the time, there were plenty of people, some competent and some rather less so, around him pushing him to war; for more information Duel of Giants by David Wetzel is a great read.

Regardless, both sides intended to use the war to bolster public support, which was high on both sides as the war broke out.