The Institut de physique du globe de Paris operates around 11 magnetic observatories located on 5 continents. These observatories are installed in areas far from the influence of human and industrial activity, and measure the intensity and direction of the Earth's magnetic field once every second. Equipped with instruments designed in our laboratories, they quantify phenomena with timescales ranging from a few seconds up to several decades. They provide information on the structure and the dynamics of the Earth core, as well as the Earth-Sun interactions. These data are used for basic research, satellite navigation or space weather forecasting.