When you arrive at the Bibliothèque Mitterrand station, take Exit n°3 (also called “Rue Goscinny”). Go left on Avenue de France, take the second left (Rue des Grands Moulins), go straight, and take the footbridge that goes over a small park. When you reach the esplanade that is behind the park, La Halle aux Farines is the long building on your right.