Complex sentence: This document called for a constitution similar to that of Napoleon's creation of the grand Duchy of Warsaw the only differences being that the representatives of the nation be elites of the municipal chamber, as was perilously the case.
Split into simpler sentences: This document called for a constitution similar to that of Napoleon's creation of the grand Duchy of Warsaw. The only differences were that the representatives of the nation be elites of the municipal chamber, as was previously the case.