Say you are a company that builds and operates large retail stores, selling consumer goods at desirable prices and that you have been successful across the land. Let's call you ... oh, Walmart.
Now, let's say you want to open some stores in Washington, D.C. and that, in accordance with the law, you are prepared to pay minimum wage for entry and low-level employees. This is known, in the trade, as "how you do business."
Well, you have a problem. Washington, D. C. does not want your lousy minimum wage jobs. (Or you, it seems.) To keep you out, it passes a law requiring you to pay wages well above minimum as defined by law and which, interestingly, is more than the city's lowest paid employees.
According to a recent and hastily passed law, you must pay $12.50 an hour. Meanwhile, according to the D.C. Department of Human Resources:
... some full-time school maintenance workers and custodians make $11.75 per hour. The rate for a clerk at the University of the District of Columbia is $10.40.
Don't be. It's D.C.