I've heard conflicting things on what, if anything Bismarck wanted to annex from France during the Franco-Prussian war.
General consensus seems to be Moltke insisted on at least the full annexation that occurred in OTL and he was in line with the clear majority of German public opinion.
As for Bismarck, the range seems to be anywhere from Bismarck wanting to annex no French territory to wanting to annex somewhat less than what was taken in OTL.