I worked in a Iranian police office for two years, and it was common to see women being mistreated by the so-called Morality Police on Tehran's streets. The Morality Police have not been trained in any aspects of moral studies, but have have been given the authority to stop people on the street, give them advice on their outfits and ask for immediate action. People can be arrested if they do not follow this advice, on the grounds of abusing the Islamic hijab. This has become a social phobia in Iran.
Stories from people who have dealt with the Morality Police show that there are no clear laws and rules in place; the Morality Police treat people according to their own personal wishes. A husband and wife who were arrested say that it occurred because the wife was wearing a white outfit. The Police forced the wife to sit inside a minibus in Narmak Square in Tehran, while photographers from different agencies took pictures. When the husband complained about the situation he was also arrested and taken to the police station. This is only one of the minor cases that acts to suppress dissent - treating people who wear 'different' outfits as though they are not a part of society and have to be taken away. Sometimes activities by the Morality Police are reported in the Western media (eg here and here) but usually they are not.
The Morality Police's authority is based on the principle of "commanding right and forbidding wrong" in Islam. This principle says that anyone can stop another person if they are acting against Islamic rules and can be shown "the right way". This principle does not value any type of social freedom of individuals. It is also common for members of Basij (an organisation mainly designed and run by the revolutionary guard) and Mullahs to give instruction regarding people's dress and make-up on the street. The government is also encouraging this action by various propaganda techniques.
There is some pushback from ordinary Iranians, seeking to live a life just slightly more free than the Morality Police may consider appropriate. But it is a sad state where such a rigid and absurd dress code is imposed.