Creating the Institut Lagrange de Paris (ILP) recognizes a remarkable concentration of expertise at its member laboratories, all affiliated with the Sorbonne University and the CNRS. The core of the ILP is based on three laboratories:

The Institut d'Astrophysique de Paris (IAP), Sorbonne University and CNRS UMR 7095,
The Laboratoire de Physique Nucléaire et des Hautes Energies (LPNHE), Sorbonne University, University Paris Diderot and CNRS UMR 7585,
The Laboratoire de Physique Théorique et des Hautes Energies (LPTHE), Sorbonne University and CNRS UMR 7589.

Two other institutions have a special role in our institute:
The Fédération de Recherche Interactions Fondamentales (FRIF),
The Institut Henri Poincaré (IHP).

The Fédération de Recherche Interaction Fondamentales (FRIF) was created in 2005, to foster collaboration between the LPTHE, the LPNHE, and the Laboratoire de Physique Théorique of ENS (LPTENS). The Institut Henri Poincaré is a strong component of our project with its capability to host schools and workshops in addition to provide meeting rooms and auditoria. Some of the topical schools, workshops and colloquia organized by the ILP will take place in the IHP. Moreover, the ILP, will follow the IHP internal program of schools to develop collaborations with scientists at the borders of the ILP direct interests.

Also associated to the ILP are teams from:
The "Galaxies et Cosmology" group from the Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique (LERMA, Observatoire de Paris, Sorbonne University and CNRS) - Françoise Combes,
The Collège de France, Chaire Galaxies et Cosmologie - Françoise Combes.