This research explores the spread of unreliable information on Facebook during the 2017 French presidential campaign. By analyzing information-sharing behavior on 252 Facebook pages, our study highlights the wide variety of information sources shared by several political communities, notably news published by partisan websites or activist blogs. Our results demonstrate that political parties – particularly, those on the extreme ends of the political spectrum – tend to re-share a large amount of information reflecting the same ideological positions as their own. (...) This trend is amplified by a phenomenon of endo-citation, that is, a “circular circulation” of information between Facebook pages within the same political community. Our results focus on the information practices of the far-right, tracing a clear over-representation of sources that are unreliable or likely to relay disinformation. We argue that this circular transmission of information creates an “unreliable information bubble” that characterizes far-right information-sharing behavior. (shrink)