Abstract: To begin with, I will introduce the equivalence principle and remind why it is one of the pillars of our current understanding of fundamental physics. Then, I will present several possible manifestations of a violation of the equivalence principle, before focusing on the universality of free fall. After talking about potential theoretical reasons why one may expect such a violation, I will present the last result obtained at the Observatoire de la Côte d'Azur, with the data from Lunar laser ranging. Thanks to a new model of the Lunar interior on one hand, and to the use of an additional wavelength for the laser, we were able to constrain a combination of parameters corresponding to violations of both the weak and the strong equivalence principles at the 7.10-14 level. Finally, I will explain why Lunar laser raging is complementary to the CNES's satellite MICROSCOPE (or Eöt-Wash experiments), which recently constrained parameters corresponding to a violation of the weak equivalence principle at the 2.10-14 level.