In this series of lectures, I propose to give a broad introduction to modern cosmology. Starting from the discovery of the Hubble law, I will show how the geometry of the Universe is described today in terms of a few cosmological parameters accounting for the expansion, the acceleration, the dark matter density, etc. I will explain why modern cosmology generally assumes a stage of inflation in the very early Universe, and give some hints on the formation of the cosmic microwave background anisotropies, which provide the most powerful observational test of our understanding of the Universe.
