Many shops in Tehran are displaying colorful Christmas decorations and ornaments welcoming the Christians who are busy shopping ahead of the the Armenian Christmas on January 6.
Although a minority religious group in Iran, Christians of Iran are free to practice their religion and perform their religious rituals.
Source: http://www.payvand.com/news/14/dec/1166.html
Christmas 2014 in Iran – Christmas Shopping, Part 1 can be found here: https://theotheriran.com/2014/12/25/photo-gallery-christmas-2014-in-iran-christmas-shopping/
Another good read on Iranian Christians is available here: http://www.al-monitor.com/pulse/originals/2014/12/iran-christians-armenians-christmas-rouhani.html##ixzz3NFNpgGCg