Iranian police said they had closed more than 800 clothes shops to stop them selling "unconventional" women's coats, state media reported on Monday.
A further 3,000 shops have been sent warnings, the IRNA news agency reported.
A new fashion for women’s coats — known as “manteaux” in Iran — with English phrases printed on the back had attracted the attention of the authorities, who passed new regulations in July.
The coats in question tend to have nonsensical phrases such as “Keep Calm I’m the Queen” written on them, but they also have short arms and no buttons in the front.
Under Iranian law, women must wear a manteau, or similar item, that loosely covers the whole body from the neck down to the knee.