Md. Code, Real Property § 14–311

(a) A commercial leasing brokerage agreement between a broker and an owner may not waive or require the broker to waive the right to claim or establish a broker’s lien.

(b) Any waiver provision made in a commercial leasing brokerage agreement or any other contract, express or implied, between a broker and an owner made in violation of this section is void as a matter of public policy.