Although in the liberal doctrine parliaments are the institution through which politics is supposed to depart from 'the art of secrecy'?, the ways in which their activities are publicized fail to generate a regime of transparency vis-à-vis the electorate. By comparing two controversies, one French and the other British, the author shows that the framing of mediated visibility of parliament participates in a process that limits the extension of parliamentary deliberations to the public. Relating parliamentary debates in the press opens the chambers to the outside, but this opening is bounded by the modalities of institutionalization of journalists' presence in parliament. Likewise, the appearance of television reactivates conflict on mediated visibility reduced by the invention of ad hoc forms of control.