What a Thunderclap (Metaphor)
After Hamel announces to the class that the French language will no longer be taught in Alsace-Lorraine, Franz comments on the shock of receiving the news, calling Hamel's words "a thunderclap." With this metaphor, Daudet's narrator emphasizes the suddenness of the announcement by equating it with the loud, disrupting sound of thunder.
Looked Like Little Flags (Simile)
During the cursive lesson, Franz comments on how the slips of paper that say "Alsace, France" which Hamel distributes for the students to copy look "like little flags floating everywhere in the school-room, hung from the rod at the top of our desks." In this simile, Franz sees the common sight of cursive copy slips anew; under the circumstance of his native language being removed from his lessons, Franz interprets the slips as flags planted in the territory of the students' desks. Hamel would like to remind his students that the desks belong to Alsace-Lorraine and not the Prussian invaders.
As If They Had the Key to Their Prison (Simile)
Before beginning the grammar lesson, Hamel digresses to remind his students about the importance of learning and protecting their native language. With their language and culture under immanent threat from the invading Prussians, Hamel instructs his students to guard the French language "because when people are enslaved, as long as they hold fast to their language it is as if they had the key to their prison." In this passage, Daudet uses simile to liken knowledge of one's native language to a key that lets them escape the prison that is the forces seeking to oppress and control them.
