What has been put up on the bulletin- board?

Hint: This question is from the tale 'The Last Lesson' which illustrates the human propensity to do stuff for plenty of time; thus, man tends to defer life's lessons, denying the fact that life is subject to transition. The last lesson in French, taught by M. Hamel symbolizes the lack of language and France's loss of liberty.

Complete answer:
The French Alsace and Lorraine regions were taken over by the Prussians. The bulletin board then showed the news that in the schools of Alsace and Lorraine, an order had arrived from Berlin to teach only German. It was appropriate to suspend the instruction of the French language. For any news and announcement, a bulletin board was set up at the Town Hall. For the last two years, because of German professions, it was a place of considerable significance. At the town hall, the Bulletin Board was infamous for presenting news and alerts on orders and announcements received from Berlin. Franz came across a crowd reflecting on the latest news from Berlin that day while walking through it, leading to a noticeable silence at the academy.

Note: The bulletin-board hanging outside the town hall illustrates the tyranny of the Prussian occupiers who occupied the Alsace-Lorraine region, where the narrator's village, Franz, is situated.
At the end of the novel, it is contrasted with the blackboard, an instrument of education that M. Hamel and his students have recourse to the intense sense of patriotism and defiance that the teacher uses to inscribe and affirm him and the villagers.