I think I may have found the origin of the whole "Éléonore eavesdrops on all of Robespierre's conversations" trope (to be fair, it could technically really be Victoire, but that seems unlikely): in the Memoirs anecdotiques of some guy named Lombard de Langres. Here's the passage in question, in which Robespierre and Danton have an argument right before the fall of the Dantonistes. Yes, it's one of *those* scenes. In any case, I'm assuming the author's "source" for this scene is the mysterious conventionnel T*, who supposedly has ties to both Robespierre and Danton and who is portrayed as the only other person present (well, aside from Éléonore). Assuming this T* exists, I could probably figure out who he is if I cared enough, but I don't, so we'll just preserve his anonymity. Besides, whether he exists or not, his information is rather doubtful, as this passage implies and as others indubitably prove.
"La conversation s'échauffait, et Danton hors de lui semblait ne vouloir plus garder de mesure, lorsque la fille du menuisier Dupleix [Duplay], chez lequel était logé Robespierre, sortit subitement d'un cabinet ou alcôve enfoncé, d'où probablement elle avait tout entendu, et dit à Robespierre : Il y a là-bas plusieurs députations qui attendent depuis longtemps, ne voulez-vous pas les recevoir ? Qu'on les fasse monter, dit Robespierre. Alors, cessant toute discussion, et laissant Robespierre plus animé contre lui que jamais, Danton s'éloigna, suivi de T*."
("The conversation was heating up, and Danton, beside himself, seemed not to want to keep any measure of moderatoin, when the daughter of the cabinetmaker Dupleix [Duplay], in whose house Robespierre was a lodger, suddenly came out of a little room or hidden alcove, from which place she had probably heard everything, and said to Robespierre: There are several deputations here who have been waiting a long time, do you not want to receive them? Let them come up, said Robespierre. Then, ceasing all discussion, and leaving Robespierre more animated against him than ever, Danton went away, followed by T*.")
...Don't ask me why all the names are italicized. I haven't the slightest clue.
"La conversation prenait le ton d'une dispute et d'une vive querelle... Au moment où Robespierre allait répliquer, mademoiselle Duplaix [Duplay] sortit d'un appartement intérieur, et dit à Robespierre :
- Maximilien, il y a là plusieurs députations des départements qui veulent te voir ; elles attendent depuis longtemps : les ferai-je entrer ?...
- Fais les monter, dit Robespierre.
Danton fut alors entraîné presque violemment par Tallien au moment où sa colère lui donnait une telle fureur qu'il serait peut-être porté à quelque extrémité envers Robespierre, qui, toujours armé, toujours entouré de vingt ou vingt-cinq misérables qu'il appelait sa garde, aurait tué ou fait massacrer Danton sur l'heure, sous le prétexte de tentative d'assassinat."
("The conversation took the tone of a dispute and a lively quarrel... At the moment when Robespierre was going to reply, Mademoiselle Duplaix [Duplay] came out from an interior apartment and said to Robespierre:
'Maximilien, there are several deputations from the departments that want to see you; they have been waiting a long time: shall I let them in...?'
'Have the come up,' said Robespierre.
Danton was then dragged away almost violently by Tallien at the moment when his anger put him in such a fury that he would perhaps have been carried to some extremity against Robespierre, who, always armed, always surrounded by twenty or twenty-five wretches whom he called his garde, would have killed Danton or had him massacred on the spot, on pretext of attempted assassination.")
...At least she doesn't explicitly accuse Éléonore of eavesdropping. On the other hand, I think accusing Robespierre of looking for excuses to have Danton murdered in his own room is sinking to a new low, even for someone like d'Abrantès.
I won't try to determine the real origin of this anecdote; whether both authors got it from Tallien or one got it from Tallien and the other copied it or one made it up and then the other copied it, it's obviously equally useless as a historical document. On the other hand, it does nicely demonstrate the fuckwittery of Thermidorian-influenced accounts...