The final appearance of a project may occasionally conceal aspects of its creative process. A process along which ideas develop, evolve and are transformed by dis-carding interesting features which do not show on the final execution of the work. In order to discover the key elements that drove that evolution, it is necessary to examine the documents that were dispensed with, both while the project was being developed and during its execution. This practice is even more significant when a broad team of professionals, which makes decision-making more complex, undertakes the project. This paper intends to give some light to the process Gilles Clément, one of the most paradigmatic landscape architects in the last decades, went through while developing his project for André-Citroën Park, and it will do so through his sketchbooks and some scarcely known documents from his own personal archive. From the first sketches to the final proposal, the process to establish the main lines and the difficulty in the realization of the work, everything will be studied in order to understand how the designer experienced the creative process of his first important project of a public space, which has become one of the most emblematic parks in Paris.