Social infomediation, a phenomenon combining online platforms and social ensembles, has been debated for several years. This study contributes to this debate by analyzing a large sample of French-speaking Twitter users, focusing on the sharing and discussion of news items. Although we do observe the "variable geometry" of communicative practices stratified on multiple levels, the thematic agenda of the most shared and discussed topics largely mirrors the wider news agenda. As opposed to studies focusing on the US, we detect a mainstream rather than political polarization, albeit one whose hegemony is far from absolute.