From the first papal bull condemning Jansen's Augustinus in 1642, which was followed by many others, including Unigenitus in 1713, until the suppression of its adversary, the Company of Jesus, in 1773, Jansenism was at the core of religious and parliamentary quarrels in the seventeenth and eighteenth centuries and generated intense activity in the publication of spiritual and theological, but also political and satirical works. The Mazarine has defined its Jansenist collection since the nineteenth century as covering all works by authors said to be Jansenist and by their opponents, as well as all theoretical, official, topical or polemical publications defending or opposing this movement, or examining its history. It also includes works which do not deal with Jansenism, but whose authors claim to be Jansenists.

The Jansenist collection in the library has been built up since the seventeenth century. At the head of the first list of acquisitions made in 1643 by Gabriel Naudé for Mazarin's library is a copy of the Augustinus, published in Paris in 1641, a year after the original edition (BnF, n.a.f. 5764, f. 16). It has grown considerably since then, firstly through ordinary acquisitions, then through massive revolutionary confiscations, particularly from the great St Victor abbey in Paris. It was consolidated by several special contributions, such as the Armand-Prosper Faugère bequest in 1899, or the donation, in 1992, of part of Augustin Gazier's library. Gazier had been president of the Société des amis de Port-Royal from 1913 to 1932.
Official documents or pamphlets were frequently bound in artificial collections in the seventeenth and eighteenth centuries, in chronological order or grouped by subject. These now form a remarkable collection in two different formats, in quarto and in octavo. Official documents (pastoral letters, letters patent and proclamations) were usually printed in quarto; the Library has a fine set of 38 volumes due to revolutionary confiscations, bound in green parchment and entitled "History of Jansenism." Critical writings or lampoons were more often in octavo, which was easier for the public to handle (in this format, the Library has most of the satirical pamphlets known as the "Sarcelades").

The collection was being described (systematic examination of the collections, cataloguing book in hand, restoration) with the support of the Agence bibliographique de l'Enseignement supérieur.