The physics at high intensity is becoming a very active field of research, benefiting from the emergence of PW-class laser projects all over the world, as well as remarquable progresses in numerical modeling and theoretical developments. On the Plateau de Saclay, the EquipeX CILEX will offer a unique experimental ensemble around the APOLLON10P laser for the French community to explore the physics at ultra-high intensity. The workshop will permit to scientists involved in these new PW-class projects to exchange and to gather their unique technical and scientific expertises, essential for the achievement of all these ambitious research programs. This first meeting will be held on 23rd-24th of January 2012 in Amphitheater Stourdzé, Ministčre de l’Enseignement Supérieur et de la Recherche, in Paris. It is supported by Laser Lab-Europe through Networking Activity on Ultra-High Intensity Ultrashort Lasers (NAUUL), the Commissariat ŕ l’Energie Atomique et aux Energies Alternatives, Science of Matter Division (DSM), the Institut of Lasers and Plasma (ILP) and the Triangle of the Physics (RTRA). There is no fee but the registration is mandatory