"La foire aux cancres " was first a best-seller, a book who spawned more works of the same genre; as many French people , I read it when I was young: it does not tell a story ,it's a collection of schoolboy howlers ,in every subject:grammar and literature,maths,history ,geography ,science ,et al .Hence the difficulty to transfer this "dunces fair" to the screen ; the script looks like a collection of more or less disjointed sketches, sometimes terribly dated .The most interesting is the depiction of French schooling before the 1968 upheaval which changed everything for better or for worse; in those by-gone days ,the teachers were on their platform , dominating their pupils ;they were respected , and their sentences were sacred( hence the mayor's egregious gaffe about Henri the Fourth's minister Sully) .A time you did not have to be educated to make your way of life (now that people are more educated, they sometimes find it hard to get a job),should you believe teacher Dominique Paturel .It was the time when absolutely undecipherable trains passing each other maths problems were given to helpless innocent kids .A time capsule .