Your employer should have withheld the city tax and sent it to the city so you do not have to file a separate city return.
Denver occupational privilege tax is also known as OPT or head tax.
The occupational privilege tax consists of two distinct parts: the
employee occupational privilege tax and the business occupational
privilege tax. The tax is imposed on individuals who perform sufficient services within Denver to
receive as compensation from an employer at least five hundred dollars
($500) for a calendar month.