Complex sentence: On 15 July 1918, Ludendorff launched his final "victory offensive" with again the aim of taking Paris, the Champagne Offensive which was stopped by the French 4th Army.
Split into simpler sentences: On 15 July 1918, Ludendorff launched his final "victory offensive", the Champagne Offensive, again with the aim of taking Paris. It was stopped by the French 4th Army.