It shall be unlawful, regardless of any contract, lease or other obligation heretofore or hereafter entered into, for any person to demand or receive any rent for any housing accommodation in excess of the legal regulated rent, or otherwise to do or omit to do any act, in violation of any regulation, order or requirement under the RSL or this Code, or to offer, solicit, attempt or agree to do any of the foregoing. In addition to the definition contained in section 2520.6(c) of this Title, the term rent, as hereinbefore defined, shall also include the payment by a tenant of a fee or rental commission to an owner or to any person or real estate broker where such person or real estate broker is an agent or employee of the owner employed by the owner in connection with the operation or management of the building in which the housing accommodation is located, or where the owner or his or her employee refers the tenant to such person or such real estate broker employed by the owner in connection with the operation or management of the building, for the purpose of renting the housing accommodation, or where there is common ownership, directly or indirectly, or a financial interest between the owner and such person or real estate broker.