Complex sentence: The Bourbon Restoration existed from (about) 6 April 1814 until the popular uprisings of the July Revolution of 1830, except for the "Hundred Days", in 1815 when the return of Napoleon forced the Bourbon monarchy to flee France.
Split into simpler sentences: The Bourbon Restoration existed from (about) 6 April 1814 until the popular uprisings of the July Revolution of 1830. There was an interlude in 1815--the "Hundred Days"--when the return of Napoleon forced the Bourbons to flee France.