First, the Artemis Accords go beyond simply rejecting the unpopular 1979 Moon Agreement [unoosa.org], which declared lunar resources to be the "common heritage of mankind" and committed parties to establish an international regime to oversee space mining. Only 18 countries have signed the treaty.
In its place, the accords envisage a US-centric framework of bilateral agreements in which "partner nations" agree to follow US-drafted rules.
Second, the accords introduce the concept of "safety zones" around lunar operations.
Although territorial claims in space are prohibited under international law, these safety zones would seek to protect commercial and scientific sites from inadvertent collisions and other forms of "harmful interference". What kinds of conduct could count as harmful interference remains to be determined.
Robert Heinlein explored the notion in a novel [wikipedia.org]. Does the future of space exploration lie with governments, or corporations?