Question

How did the lessons of the franco-prussian war help to initiate world war 1?

Answer 1

The answer is States developed offenses that could be mobilized rapidly, which is what happened at the start of World War One.

One of the famous tactics that used by Prussia against france during Franco-Prussia war was the rapid offense using a superior number of armies
to cut off opposition army before they could even make proper response.
 This same tactic was used by Germany when they initiated the war.