Step 1: Understanding the Concept:
The bulletin board at the town hall was the source of all information and often "bad news" during the Franco-Prussian war.
Step 2: Detailed Explanation:
In "The Last Lesson," Franz notices a crowd in front of the bulletin board.
The board carried an official order from the Prussian authorities in Berlin.
The order dictated that the French language would no longer be taught in the schools of Alsace and Lorraine.
From the next day, a new German teacher would arrive, and German would be the only language of instruction.
Step 3: Final Answer:
The board carried the news of the linguistic cultural imposition by the Prussians.