What are the most notable aspects of the narration within Pere Goriot?

One of the most striking aspects of Père Goriot, or Father Goriot, is the opening passage, which describes the decaying state of Madame Vauquer's boarding house. The passage is noted for its rich detail and its lack of sentiment.
The boarding house and its district -- "between the Latin Quarter and the Faubourg Saint-Michel" -- are described by a rather intrusive narrator who speaks directly to the reader. On the first page, the narrator describes the story as a drama, acknowledges the overuse of the word, but insists that "it must do service again here, not because this story is dramatic in the restricted sense of the word, but because some tears may perhaps be shed...before it is over." This type of narrative device, which anticipates the thoughts and feelings of the reader, is common in nineteenth-century literature.
One of the best-known passages of this novel is that in which Balzac directly identifies his bourgeois reader, sitting in a comfortable chair, expecting to be amused by a story that will actually cause outrage. Balzac then distinguishes between this tale and the exaggerated "[romance]" that the reader will expect: 

Ah! once for all, this drama is neither a fiction nor a romance! All is true,—so true, that every one can discern the elements of the tragedy in his own house, perhaps in his own heart.

Père Goriot, like much of Balzac's writing, is classified as part of the Realist tradition. Realist literature is characterized by an interest in social dilemmas and a lack of interest in the sentiment and Sturm und Drang of Romantic literature. Realism sought to portray things as they are. The "crumbling stucco" between Montmartre and Montrouge, for example, are visual reminders of that which is left behind in the wake of civilization's triumphant course.
His appeals to the reader and his critiques of a society indifferent to "poverty and dullness, old age lying down to die, and joyous youth condemned to drudgery" are designed to arouse the reader's outrage and sympathy, not our sentiment, which is a feeling that allows for distance and self-indulgence.