Complimentaillerie is a word that might fit the bill. It is defined in Le Trésor de la langue française as pejorative, and as a compliment that is more like a mockery than praise. It is not very juteux, but it was still worthy of Verlaine’s attention:

Parbleu ! je sais bien qu’on peut, qu’on va, sans doute me dire : « Comment vous ! le créateur subtil de rythmes, le rimeur rusé s’il en fut » — et telles et telles complimentailleries plus ou moins, plutôt moins, sincères — « vous venez nous préconiser ces vers pour la plupart médiocrement rimés et d’une allure parfois maladroite, gauche » — et tous les et cœtera [sic] de partisans, au fonds et au tréfonds, de mauvaise foi, d’une impossible impeccabilité.

— Paul VERLAINE, Œuvres posthumes

There is also a very common phrase in Quebec, though it appears to be specific to this region, that states…

Après les fleurs, le pot !

The flowers are the praises, and they are usually (figuratively) thrown at the people we praise (compare with jeter des fleurs à quelqu’un). The flowerpot is then also expected to be thrown, causing a bit more damage and discomfort.

I am not familiar with the usage of “to damn with a faint praise”, so I am unsure if its mechanism involves any further developments after the faint praise. If it is the case, then “après les fleurs, le pot !” could work. If not, then it could be possible to modify it slightly, and people (at least in Quebec) would notice the link with the expression. Possibly something along these lines:

• Après ces maigres fleurs, je n’attendrai pas (je n’ai pas attendu) qu’on me lance le pot !
• Avec ces fleurs fanées, on devine l’arrivée du pot !

Since you were also looking for something Hugo or Zola might have said, one could consider quoting Baudelaire, and replace “ces maigres fleurs” or “ces fleurs fanées” with “ces fleurs maladives”

Among many many other funny one liners, the writer and humorist Robert Lassus offered his own twist on the expression être dans la fleur de l’âge, which usually expresses the peak years of one’s life, before the decline begins.

Je suis dans la fleur d’un âge qui commence à sentir le chrysanthème.

Here, the chrysanthemum represents death, following the very strong symbolism this flower has in some European countries, including France & Belgium (and therefore in the French language in general).

Though unattested,

• Le patron m’a lancé des fleurs ! Des chrysanthèmes ! or
• Le patron m’a jeté un bouquet de chrysanthèmes.

would carry the sense of ending conveyed by the damnation part of the English expression, as well as the praise part (through “lancer des fleurs”), and I believe it would be well understood.

One possible downside of such an expression is that it could make people smile, because it is unusual and somewhat unexpected, whereas the English original is a cemented expression that has a set form and can be used without any type of sarcasm, even though it describes a sarcastic behaviour.

In order to familiarize myself with the expression, I looked around and found the following discussion about an extract of Jane Austen’s Emma:

First a quote from the source:

[Mrs Elton] had a little beauty and a little accomplishment, but so little judgment that she thought herself coming with superior knowledge of the world, to enliven and improve a country neighbourhood…

Then a discussion about the repetition of “little”:

The effect here is clear: the two first occurrences are contained in a concessive construction, granting Mrs Elton at least a modicum of positive characteristics, before the final “little”, modified by “so”, reveals the true purpose of the first two occurrences: to damn with faint praise.

This example is clearly a sober use of the expression, and everything I suggested so far has been mostly to express one’s disarray about receiving such a treatment, not about discussing it from an external perspective. They are not necessarily inappropriate, since as far as I know French doesn’t have a clear absolute translation of the expression, and therefore we can vary the translation depending on the context, but none of them would really work here.

“Complimentaillerie” is way too sarcastic to translate the sentence.

Similarly, we could easily dismiss “Après les fleurs, le pot !”, though it is a fixed expression that could be used in other contexts, as having the wrong grammatical structure and being hard to put as a linking feature between two parts of a sentence.

And as far as “on lui a jeté un bouquet de chrysanthèmes” goes, it is probably a little too exotic and arguably a bit too weak. So for this specific instance, I would suggest considering yet another possible translation:

L’effet ici est clair : on utilise deux fois « peu » sur le mode de la concession, conférant à Mrs Elton au moins un soupçon de traits positifs, avant d’asséner ce « si peu », qui révèle la véritable intention des deux premières itérations : fleurir le tombeau qu’on lui prépare.