In February 1848, the people of Paris rebelled against their king. When this news reached the Germans, they also rebelled. In Austria, rioting and demonstrations forced the chancellor to resign. In Berlin, people defied the army and forced the Prussian king to appoint new ministers and to promise a constitution. Similar rebellions occurred in most other German capitals. Many Germans hoped that they could replace the Confederation with a more unified nation. In May, an elected assembly met in Frankfurt to write a new constitution.

However, some people began to lose interest in the revolution. Others disagreed about its goals. Meanwhile, the governments began to recover. In October 1848, Austrian troops recaptured Vienna. In December, the new Prussian assembly was dissolved by troops.

The Frankfurt Assembly was divided on many issues, especially on whether Catholic Austria or Protestant Prussia should be the leading power in the new German nation. In March 1849, members compromised on a constitution that called for an emperor and a two-house parliament. The Prussian king Frederick William IV was invited to be emperor but he refused. The assembly then broke up. The revolution was defeated in the spring of 1849. The German Confederation of 1815 was reestablished.