The sentence with the text in bold means:
The little cardinals of the Church of Letters that then bustled about between the Holy See of Sébastien-Bottin street and the Sistine Chapel of Jacob street promulgated the canon law of the novel and poetry.
After a bit more research, I found Emmnuel Le Roy Ladurie's review of Régis Debray's Teachers, Writers, Celebrities: The Intellectuals of Modern France in the New York Review of Books in January 1982. The street names refer to two important publishing houses in Paris, France (emphasis added):
Debray is more like an ideological Baedeker or Fodor of the Parisian intellectual world—a deeply disapproving guide, it must be said, for Debray ultimately wants to show that the various “media” of the French intellectual world, and the people who he thinks control them, make up an oppressive network of power in support of “bourgeois” values. He gives us first a geography of publishing. There are two poles: rue Sébastien Bottin, with the great publishing house of Gallimard; and rue Jacob, supplemented by the adjacent rues Guénégaud and de Seine, where we find the headquarters of the intellectually prominent house of Le Seuil. Both poles are on the Left Bank.
In other words, Gallimard (rue Sébastien Bottin) and Le Seuil/Editions du Seuil (rue Jacob) are two influential publishing houses that dictated "bourgeois" values. (The publishing houses Gallimard and Le Seuil are only a seven-minute walk away from each other, according to Mappy.fr.)
The article Die Dreierbande Galligrasseuil by J. Fritz-Vannahme (Die Zeit, October 1989) discusses the "gang of three" Galligrasseuil, i.e. Gallimard, Grasset and Le Seuil, which wins the lion's share of revenue-generating literary prizes in France:
Man, das ist vor allem die Dreierbande Galligrasseuil, ein "Syndikat" der Renommierverlage Gallimard, Grasset und Le Seuil. Das Gros der großen, umsatzträchtigen Literaturpreise entfällt seit zwanzig Jahren auf sie.