In A Tale of Two Cities, what rhetorical devices does Dickens use to portray the weaknesses and vices of the French aristocracy in Book 2 Chapter 7?
The presentation of the aristocracy in this novel range from the menacing and cruel to the absurd. Your selected Chapter presents one of the more absurd examples, when we are presented with Monseigneur:
Monseigneur was in his inner room, his sanctuary of sanctuaries, the Holiest of Holiests to the crowd of worshippers in the suite of rooms without. Monseigneur was about to take his chocolate. Monseigneur could swallow a great many things with ease, and was by some few sullen minds supposed to be rather rapidly swallowing France; but, his morning's chocolate could not so much as get into the throat of Monseigneur, without the aid of four strong men besides the Cook.
This passage is clearly dripping with irony - note the ironic religious allusion to the "Holiest of Holiests", clearly indicating the absurdly high prestige and position in society that Monseigneur had. Also note the "few sullen minds" that comment how Monseigneur is in danger of swallowing France - reducing it to a state of absolute poverty while he drinks deep. The absurdity of the necessity for four strong men to convey Monseigneur's chocolate is likewise highlighted.
This is just one example, of course. If you read the rest of the chapter you will hopefully be able to identify plenty more examples of how Dickens presents the weaknesses and vices of the French aristocracy in an amusing light, using this example to guide you. Good luck!