Résumé : How will the Paris Agreement drive countries to address climate change? One expectation of the Agreement is that transparency will stimulate countries to increase the ambition of their pledges by revealing information on Parties’ climate efforts. To this end, the Agreement introduced a new ‘enhanced transparency framework’ (ETF) to report and review information on Parties’ greenhouse gas emissions, progress made in implementing and achieving nationally determined contributions (NDCs), their adaptation actions, and the financial, technological and capacity-building support needed, received and provided to developing country Parties. However, this relationship between transparency and progressive ambition over time remains largely untested. In this article, we first outline several pathways through which increased transparency could potentially lead to increased ambition. These pathways notably depend on the availability of comparable, complete and timely information on the performance of Parties. By reviewing the experience with past and existing transparency arrangements, we identify four types of challenges that will likely pose barriers to the generation of such information by the ETF, and suggest some efforts that might address these challenges to support greater ambition in future rounds of NDCs.Key policy insights:. The potential use of the flexibilities offered to developing countries on some dimensions of the ETF may lead to the generation of incomplete and incomparable information.. It will be difficult to assess and compare progress made by Parties towards achieving their NDCs due to heterogenous, qualitative and conditional NDCs; the variety of indicators that Parties will choose to track their progress; and to weaknesses in the reporting guidelines on climate action and support.. Despite ongoing efforts to address this, the information generated by the ETF may be outdated and non-comprehensive due to capacity gaps.. The apolitical design of the ETF means that it will not lead to judgments, for example on the level of ambition of an NDC, or even on whether a country is achieving its NDC. The ETF is also not equipped to deal with cases of political unwillingness to participate in the ETF itself.