  We present two projects aiming to probe key aspects of the theory of General
Relativity with high-precision quantum sensors. These projects use cold-atom
interferometry with the aim of measuring gravitational waves and testing the
equivalence principle. To detect gravitational waves, a large multi-sensor
demonstrator is currently under construction that will exploit correlations
between three atom interferometers spread along a 200 m optical cavity.
Similarly, a test of the weak equivalence principle is currently underway using
a compact and mobile dual-species interferometer, which will serve as a
prototype for future high-precision tests onboard an orbiting satellite. We
present recent results and improvements related to both projects.
