There follows a totally non-representative, rather arbitrary and fairly bird-heavy selection of puns. This is not anything like an exhaustive list of all the puns in this book that I'm aware of, and puns I'm aware of are themselves probably a very small subset of all the puns that are actually there, so please do add any more puns, double-entendres, unexpected meanings, strange wordplay and other related things you'd like to explain/discuss/ask for clarification on.
Anyway, just to get the ball rolling, a few examples:
Right, first, the catalyst for this thread, deHavilland on ABC/abaisse and rolled-out dough as a metaphor for the downtrodden masses here
Next up, (though it has its own thread here), Bossuet's "tire-moi mes bottes, fille de cinq louis":
"tirez-moi" - in the boots phrase, "pull off", but also "take me", and just as much of an innuendo in French as that is in English. Addressed by the original Bishop Bossuet to God in the sense "take me, Lord" (More on that half over here on tumblr).
"fille de cinq louis" -> "fille de Saint-Louis", also a line from the Bishop B., in a funeral oration for the wife of Charles I (more on that here)
While we're on the subject of Bossuet, there's the obvious Lesgles/Laigle "eagle" thing, which is relevant to the eagle as a Napoleonic symbol. Also, Meaux -> mots, words.
Now, on to the rich mine of other bird puns that certain quarters of Tumblr have been getting excited about for a while now:
Wherein Bahorel makes a disparaging comment about theatre, Combeferre responds with a comment about ducks, and gauzythreads writes several thousand words of meta on the
Long story short, a canard is a duck, a lie or tall story, and also a form of popular entertainment/early tabloid media.
Bahorel, in reference to a poster granting permission to eat eggs: "Ouailles, manière polie de dire oies." Literally, "Flock’; a polite way of saying geese.", "oies"/"geese" being a colloquialism for foolish people. More detail here, (also there: a comment regarding geese, eggs, and ownership of the means of production)
More from gauzythreads. Grantaire in Preliminary Gaities compares bankers etc. to eagles, and says he is creeped out by them, but the exact phrasing he uses is "j'en ai la chair de poule", literally "I have the flesh of a chicken", which conveys the creeped out thing, but also a comparison between himself as a chicken vs. other men as eagles. (Also - there are several instances of Enjolras being linked to eagle imagery elsewhere, make of that what you will. Also also, pilferingapples has had a bunch of things to say about Cynicism, including the thing where Diogenes responds to the definition of Man as a featherless biped by waving a plucked chicken at Plato, and suggests possibly also taking chicken comparisons as having an element of "poor excuse for a man" going on)
In non-bird-related territory, when Courfeyrac sets fire to the Charter, Combeferre's comment the charter metamorphosed into flame"/"la chartre metamorphose en flamme" -> La Fontaine "la chatte metamorphose en femme"/"the cat metamorphosed into a woman"
This is very much one of the areas where things are in a lot of danger of getting lost in translation even without the translator making actual errors, since puns are absolute hell to translate even when you're aware they're there, which a translator might not be. There are also some floating around that have got lost in some translations because the translator has actually translated the thing wrong.
An example that Pilferingapples and I turned up in conversation on Tumblr a little while ago (here) about M. Gillenormand:
Quelquefois il faisait allusion à son âge de quatrevingt-dix ans, et disait: J’espère bien que je ne verrai pas deux fois quatrevingt-treize. D’autres fois, il signifiait aux gens qu’il entendait vivre cent ans.
which is a pretty clear play on the age of 93/the year 1793 and a slam on the latter. It's...less obviously so in Hapgood, who mistranslates "d'autres fois", or in FMA, where the joke is TOTALLY missed because there you have "I really hope I shall not see 90 twice" instead of 93.
(unexpected meanings lost in translation can also probably fit in here even if they aren't actual puns)
Have at it.