In Chapter 1: The Proposition, on the billboard across the message machine are several references to the NOLF series. The opera poster is Inge Wagner from NOLF 1. The pink paper with 3 girls are the three assassins Cate needs to kill at the end of NOLF 1. La Troupe refers to La Troupe de Pantomine from NOLF 2, a group of mime cronies, headed by Pierre, who was hired by the Director to kill Cate Archer.
Also, the "how to pick up classy chicks by Steven Lee" likely refers to Steve Lee, a Senior 2D/3D Artist of Contract J.A.C.K.