A large controversy occurred in France, both in the art world and the urban planning milieu, when François Pinault gave up the idea of setting up his own contemporary art gallery at the core of the Boulogne-Billancourt urban regeneration project. It was the first private project for an art gallery on this scale in France. The objectives of this paper are to understand the reasons and the context that permitted Pinault’s volte-face and led the project to fail. This research paper will reveal some of the hidden sides of this project process. The local public authorities were criticized for their lukewarm enthusiasm for this project and for their lack of professionalism. But the duties and the responsibilities of Pinault in this failure were obviously underestimated and even concealed whereas his image and reputation as a mega collector had widely benefited from this art gallery project, in spite of its abandonment.