Carlsbad Decree of 1819: Bundestag passed many reactionary restrictions. There were uniform censorship on all periodical publication. Nationalist students clubs were disbanded. Central investigating commission was set up to ferret out conspiratorial organizations.
Zollverein (custom unions): these were formally organised under Zollverein Treaties of 1833 (enforced on 1 Jan, 1834). It unified German states under Prussia through removal of protectionist policies, improved transport of raw material, and rise of new industrial centres. Austria was not part of this union.
July Revolution in France (1830): people of France rose against the rule of Charles X, who was later replaced by Louis Phillipe. This revolutionary news spread to the German states. People began demanding constitutional reforms. However, through more Carlsbad decrees Diet was in position to silence all the constitutional demands. Austria remained immune from this revolutionary wave.
March Revolution of Germany (1848): it is the extension of ongoing revolution of Europe which started from France where King Louis Philippe abdicated his throne. People in Germany began demanding freedom of the press, trial by jury and creation of a German parliament. Fear of mass movement, rulers began providing the liberal form of government. This time revolution engulf Austria as well where chief minister Metternich was force to leave the nation.