Investments for the purpose of building, renovating, restructuring or making accessible as provided for in articles L. 111-7 to L. 111-7-4 of the Code de la construction et de l’habitation, for the benefit of a main departmental library can only be taken into account if the surface area built, the surface area renovated or the total surface area after works reaches at least the surface area existing on the date of transfer of the central lending library to the department or, if the departmental library was built after the date of transfer of the central lending libraries to the departments, on the date of its opening to the public.
In departments that do not have a departmental library, construction projects are only subject to the condition that the total surface area of the main departmental library after works is at least 1,500 square metres.
Extensions to main departmental libraries are only subject to the condition that the new surface area is at least equal to one quarter of the surface area already in existence.