The history of Grand Paris has been partly constructed around the markers provided in the major regional plans that have punctuated the development of the Greater Paris region, from the 1913 ‘Report for the enlargement of Paris’ to the 2009 ‘Grand Paris international consultation process’. By providing an epistemic framework for understanding the major regional plans, this article clearly posits that their history – i.e., both their succession and development – has a structuring impact on the ‘reality’ constituted by ‘Grand Paris’. The research we present here was conducted as part of the Inventing Grand Paris research programme with the objective of visualizing what we have termed the ‘depth of plans’, their contents and conflicts as well as their nature and temporality. To this end, a research device was created in the form of a digital ‘Atlas of Grand Paris plans’. By presenting the vast corpus of archives generated by the development of regional plans, this helps present a nuanced perspective and clarify the complexity of the metropolitan dynamics of Greater Paris. By looking at the possibilities it opens up for understanding the process, this article ultimately explores the way in which the digital humanities can contribute to the history of planning.