Two gyms and a department store were shut down for breaching Covid-19 safety measures.
A further 28 firms were hit with fines for breaching regulations as part of a clampdown led by Dubai's Department of Economic Development.
The offences were uncovered during a series of inspections of open markets and commercial premises on Saturday.
The authority said the gyms were closed for breaking "precautionary guidelines against Covid-19", while the department store was shut down for failing to enforce physical distancing protocols.
The financial penalties were issued for breaches related to the wearing of face masks and physical distancing during a sweep of Al Barsha, Souq Al Kabeer, Al Murar, Al Baraha, Oud Metha, Al Nahda, Burj Khalifa, Al Quoz, Al Bada'a and various shopping malls.
Inspectors found 480 establishments had fully complied with strict guidelines governing the operation of businesses during the pandemic.
Traders caught out included those dealing in mobile phones and accessories, document processing, textiles, travel and inbound tours. Money exchange houses, photo studios, therapeutic massage service providers, print and copy services, and physiotherapy were also on the list – in addition to gyms.
The department called on businesses to adhere to safety measures and urged the public to report infractions through the Dubai Consumer App available on Apple, Google and Huawei stores, by calling 600 545 555, or via the Consumerrights.ae website.