Let us start saying that it was when Schurz was a student at the University of Bonn, in early 1848, when news reached that the French people had removed their king and had established a representative government.
It was in that precise moment that Schurz got inspired and mmediately joined a group of revolutionaries determined to fight for civil liberties and national unity in Germany.
The answer to your question is the news that the French people had removed their king and had established a representative government.