The Cité de l’Économie housed in the renovated Gaillard hotel opened on 14 June 2019. As the building has never been fully open to the public, this visit is the first opportunityto be able to understand the three lives of this very singular private hotel. It is in fact, the witness of the neo-Renaissance privative architecture of the late nineteenth century, that of the banking architecture of the beginning of the following century, and now the reflection of museum developments that integrate the old with the contemporary to illustrate the place of cultural and heritage institutions at the heart of societal advances.