Hitler’s had said in Mein Kampf (1924) that he would abolish the Treaty of Versailles.
The first way Hitler broke the Treaty was over Germany’s armed forces. In 1934, he destroyed the League of Nations Disarmament Conference by demanding equality of arms with France and Britain – this broke the Treaty because it had set up the League with the stated aim of achieving disarmament. At first, Hitler broke the Treaty’s terms by building up his army in secret, drilling volunteers with spades instead of rifles. Then, in 1935, he openly held a huge rearmament rally. The other nations let him get away with it – Britain even made a naval agreement with Germany, accepting that Germany had a right to have a navy of 35% of the British navy (i.e. this broke the Treaty, which said that Germany could only have 6 battleships). After 1936, Hitler reintroduced conscription, and began to pump huge sums into Germany’s armed forces. Germans were told ‘guns not butter’. By 1939, Germany had 95 warships, 8,250 airplanes and an army of nearly 1m. men (many more than the 0 planes and 100,000 men stated in the Treaty of Versailles). Hitler even war-tested his armed forces in the Spanish Civil War; in 1936 he told his generals to get ready for war in 4 years’ time.
The second way Hitler broke the Treaty was over the Rhineland (declared a demilitarised zone). In 1936, Hitler moved his troops into the zone, claiming that the recent treaty between France and Russia threatened Germany’s safety. His commanders had orders to retreat if the French army tried to stop them, but this time it was France who did nothing. The League of Nations, busy with the Abyssinian crisis, also did nothing.
The third way Hitler broke the Treaty of Versailles occurred in 1938. The Treaty forbade Anschluss between Germany and Austria. An attempted Nazi putsch in Austria failed in 1934, but in 1938 Hitler tried again. Austrian Nazis organised riots, while Hitler pressurised the Austrian Chancellor Schuschnigg to declare Anschluss. Schuschnigg asked both France and Britain for help, but was refused, so he suggested instead a plebiscite. To prevent the possibility of a ‘no’ result, Hitler invaded. The Germans were greeted by a frenzied, stage-managed demonstration. Some 30,000 Austrians were imprisoned. Next month, in a referendum, 99% of Austrians voted yes to Anschluss.
By the end of 1938, Hitler was doing the same thing in the Sudentenland, which the Treaty of Versailles had given to Czechoslovakia. Sudeten Nazis, led by Henlein, caused trouble, claiming that they were being oppressed by the Czechs. Hitler demanded union, and threatened war. This time, although the Czech leader Beneš was prepared to fight, it was Britain and France who, at Munich, broke the Treaty of Versailles and gave the Sudetenland to Germany. Which just left Danzig, and the Polish corridor . . .
It can be argued that it was not just Hitler who broke the Treaty of Versailles, but also Britain and France, when they allowed him to do what he did.