It requires them to wear either a chador: a long, black piece of cloth, or a cloak-like garment called the manteau.
Not very exciting.
But Farnaz Abdoli, a fashion designer, is pushing the boundaries with her colorful and edgy clothing line called POOSH.
Anchor Marco Werman speaks with Azadeh Moaveni, author of Lipstick Jihad and editor of IranWire website.
She has been following Abdoli's work and spoke to her recently.