Le Grand Paris Financement (GPF), or Grand Paris Financing, is a critical component in the realization of the ambitious Grand Paris project, a sprawling urban development plan aimed at transforming the Paris metropolitan area into a more sustainable, competitive, and livable global city. Established in 2012, GPF serves as a specialized financial institution dedicated to securing and managing the long-term funding required to support the infrastructure projects central to the Grand Paris vision. The primary objective of GPF is to centralize and streamline the financing of major transportation infrastructure, particularly the Réseau Grand Paris Express, an extensive network of new automated metro lines intended to connect the suburbs of Paris more effectively and reduce reliance on the congested city center. This network includes several new lines circling the city, extensions to existing lines, and connections to airports and other key areas. GPF operates as a financial intermediary, issuing debt on the financial markets to raise funds. These funds are then channeled towards the Société du Grand Paris (SGP), the public entity responsible for the design, construction, and operation of the Grand Paris Express. By consolidating borrowing under a single entity, GPF leverages economies of scale and achieves more favorable borrowing terms than individual local authorities or the SGP might obtain independently. This centralized approach enhances the financial credibility of the project and ensures a stable and predictable stream of funding for the long term. The funding sources for GPF are diverse and structured to ensure the long-term financial viability of the project. These sources include a portion of the taxes levied in the Île-de-France region, contributions from the national government, and potentially, revenue generated from the operation of the Grand Paris Express. This diversified approach mitigates the risk associated with relying on a single revenue stream and ensures that the financial burden is shared across various stakeholders. Beyond its core role in financing transportation infrastructure, GPF also plays a role in supporting broader urban development initiatives aligned with the Grand Paris project. This includes investments in housing, economic development, and environmental sustainability. By strategically allocating resources, GPF contributes to creating a more balanced and integrated metropolitan area, reducing social and spatial inequalities, and fostering economic growth across the region. The creation of GPF underscores the French government’s commitment to long-term strategic planning and investment in infrastructure. By providing a dedicated financial vehicle for the Grand Paris project, GPF ensures that the ambitious vision can be realized in a sustainable and fiscally responsible manner. Its success is crucial not only for the transformation of the Paris region but also as a model for large-scale urban development projects around the world.