The CIRA is mainly a library, but it also possesses archival fonds and documentations.
The library contains documents about the anarchist history, movement and ideas, that may be borrowed or consulted on site, such as books and leaflets (20'000 in about forty languages, but mostly in French, Italian, Spanish, German and English, from 1848 to today), periodical titles (about 4000 of them, of which near a hundred are still active and a few others are in a digital format), audio and video recordings (several hundreds, partly digitized). Since may 2008, the library catalogue can be found online, and its content is regularly updated.
The archives are composed from personal, group or organisation archival holdings. They are organized depending on their provenance. In other terms, the coherence of each archival holding isn't based on the theme, but on the origin of the different pieces that form the archival holding. This section regroups a few dozen of them, that were given to the CIRA since the very beginning of its activity. They contain unique or rare documents, ranging from 1833 to the present day (but mostly from 1890 to 2000). Since 2015, the inventories have been slowly made available to the public.
There is also a good amount of information including ephemeral publications (flyers, press clippings, etc.) sorted geographically or by theme that are partly inventoried. These documents are highly heterogeneous and come from many different places. Lastly, the CIRA collects important iconographic materials: more than 4000 posters, post cards, photos and various illustrations.