A business that leases real estate and improvements (buildings, etc.) in the form of space for offices, a warehouse, a restaurant, a nail or hair salon, a clothing store, a coffee shop, or other commercial (nonresidential) space will usually be required to sign a written contract known as a commercial lease agreement.

If the tenant (the business occupying the space) who signs a commercial lease agreement fails to pay the rent on time, the landlord may have the right to charge late fees, terminate the lease, and lock the commercial tenant out of the space by changing the locks.

A commercial landlord’s ability to charge late fees generally depends on the specific language in the written lease agreement and the state's contract law.

Contract law in most states recognizes an implied duty of good faith and fair dealing between parties to a contract, and a commercial landlord who charges late fees because the tenant is an hour late paying the rent may be in breach of the landlord’s implied duty of good faith and fair dealing—unless, for example, the lease agreement specifies an hour (12:00 p.m.) of the day by which rent is due and states that time is of the essence.

In Louisiana (LA), a commercial lease agreement is a binding contract between a landlord and a tenant for the rental of nonresidential property, such as office spaces, warehouses, or retail locations. The terms of the lease agreement will dictate the rights and obligations of each party, including the payment of rent and the consequences of late payments. Louisiana law allows landlords to charge late fees if this is explicitly stated in the lease agreement. However, the fees must be reasonable and not punitive in nature. The lease may also outline the landlord's right to terminate the lease and lock out the tenant for nonpayment of rent, but such actions must comply with the terms of the lease and applicable Louisiana law. The implied duty of good faith and fair dealing is recognized in Louisiana contract law, which means that both parties are expected to act honestly and fairly in the performance and enforcement of the lease agreement. A landlord's actions, such as charging excessive late fees or locking out a tenant without proper notice, could potentially breach this duty. It is advisable for both landlords and tenants to have the lease agreement reviewed by an attorney to ensure that it complies with Louisiana law and to fully understand their rights and responsibilities under the contract.