The first was when a list member called my attention in private email to capitalization, "Was 'habit' capitalized in the English translation or in the original French?" I responded by showing two passages from Gutenberg; the first was Proust writing in French and the second was Moncrieff translating the same passage in English:
Mais cette souffrance et ce regain d'amour pour Gilberte ne furent pas plus longs que ceux qu'on a en rêve, et cette fois, au contraire, parce qu'à Balbec l'Habitude ancienne n'était plus là pour les faire durer. ...
But this suffering and this recrudescence of my love for Gilberte lasted no longer than such things last in a dream, and this time, on the contrary, because at Balbec the old Habit was no longer there to keep them alive. ...
As far as the question goes the answer is 'yes'. Even in the third sentence of the passage where Proust uses a lower case "h". Moncrieff follows him in his translation:
Le changement d'habitude, c'est-à-dire la cessation momentanée de l'Habitude paracheva l'oeuvre de l'Habitude quand je partis pour Balbec. ...
The change of habit, that is to say the temporary cessation of Habit, completed Habit's task when I started for Balbec. ...
However in the paragraph before that Proust uses the lower case 'h',
... les lois plus générales de l'habitude.
while Moncrieff capitalizes it,
... the still more general rules of Habit.
Later Kilmartin and Enright honor Moncrieff.
The second thing is in the carriage of Mme de Villeparisis, talking about Chateaubriand, beginning with page 410 of the Modern Library Edition. The Narrator is speaking:
Shyly I would quote to Mme de Villeparisis, pointing to the moon in the sky, some memorable expression of Chateaubriand ...
“And you think that good, do you?” she would ask, “inspired, as you call it. ...
... As for his fine phrases about the moon, they had quite simply become a family joke. Whenever the moon was shining, if there was anyone staying with us for the first time he would be told to take M. de Chateaubriand for a stroll after dinner. When they came in, my father would take his guest aside and say: ‘Well, and was M. de Chateaubriand very eloquent?’—‘Oh, yes.’ ‘He talked to you about the moonlight.’—‘Yes, how did you know?’—‘One moment, didn’t he say—’ and then my father would quote the phrase. ‘He did; but how in the world . . . ?’—‘And he spoke to you of the moonlight on the Roman Campagna?’—‘But, my dear sir, you’re a magician.’ My father was no magician, but M. de Chateaubriand had the same little speech about the moon which he served up every time.”
We have a real person, François-René, vicomte de Chateaubriand being spoken of by a fictional person, Mme de Villeparisis, who is retelling the stories of her fictional father. Obviously the relations reported didn't happen between the parties stated.
During a Summer in Brittany I read Mémoires d'Outre-Tombe at Saint-Malo but I know little of Chateaubriand's biography. Did the moonlight walk sequence, as reported, happen to someone else? It seems Chateaubriand's words about the moonlight "had quite simply become a family joke" could be argued as defamation especially in a French court to be settled for a single Franc or an Euro as the case may be.
How far can one go making the real into fiction in a french novel?