Artin groups seem to enjoy several nonpositive curvature features. First, I will explain how braid groups with at most 6 strands act properly and cocompactly on a CAT(0) simplicial complex (joint work with D. Kielak and P. Schwer, following T. Brady and J. McCammond). Secondly, I will describe, more generally than the classical right-angled ones, which Artin groups act properly and cocompactly on a CAT(0) cube complex (related to work of J. Huang, K. Jankiewicz and P. Przytycki).