Question

The Munich agreement was an arrangement in which the leaders of Great Britain, France, Italy, and Germany allowed Germany to annex the Sudetenland (territory of Czechoslovakia) in return for an end to further German aggression in Europe.
What German act violated the Munich agreement?

Answer 1

Hitler and his Nazis used Blitzkrieg to invade Poland, and that is what caused the start of WWII<span />

Answer 2

The Munich Agreement was a settlement permitting Nazi Germany's annexation of portions of Czechoslovakia along the country's borders mainly inhabited by German speakers, for which a new territorial designation "Sudetenland" was coined. The agreement was negotiated at a conference held in Munich, Germany, among the major powers of Europe, excluding the Soviet Union and Czechoslovakia. Today, it is widely regarded as a failed act of appeasement toward Germany. The agreement was signed in the early hours of 30 September 1938 (but dated 29 September). The purpose of the conference was to discuss the future of the Sudetenland in the face of ethnic demands made by Adolf Hitler. The agreement was signed by Germany, France, the United Kingdom, and Italy. Sudetenland was of immense strategic importance to Czechoslovakia, as most of its border defenses, and banks were situated there,[citation needed] as well as heavy industrial districts.

Because the state of Czechoslovakia was not invited to the conference, it considered itself to have been betrayed by the United Kingdom and France, so Czechs and Slovaks call the Munich Agreement the Munich Diktat (Czech: Mnichovský diktát; Slovak: Mníchovský diktát). The phrase "Munich Betrayal" (Czech: Mnichovská zrada; Slovak: Mníchovská zrada) is also used because the military alliance Czechoslovakia had with France and Britain[citation needed] proved useless and also known because of the phrase "About us, without us!" This phrase is most hurtful for people of Czechoslovakia (Czech republic, Slovakia and Subcarpathian Ruthenia). Today the document is typically referred to simply as the Munich Pact (Mnichovská dohoda).

In Germany the Sudeten crisis led to the so-called Oster Conspiracy. General Hans Oster, deputy head of the Abwehr, and prominent figures within the German military who opposed the regime for its behaviour that was threatening to bring Germany into a war that they believed it was not ready to fight, discussed overthrowing Hitler and the Nazi regime through a planned storming of the Reich Chancelleryby forces loyal to the plot.

Hope this helps.