The sanctions, now extended until 13 April 2019, include:
asset freeze and visa bans for individuals and entities responsible for grave human rights violations ban on exports to Iran of equipment which might be used for internal repression and of equipment for monitoring telecommunications
The EU initially adopted sanctions [materials] towards Iran in 2006, following a series of UN Security Council Resolutions aimed at the country's nuclear program. Those sanctions were extended in 2011 in response to "grave human rights violations" and concerns over the suppression of internal critics. This past March, UN human rights experts expressed concern [JURIST report] over two jailed human rights activists.
While the EU was unified in renewing the sanctions, there exist divisions among member states on additional sanctions. In the past month the UK, Germany, and France have been pushing for additional sanctions [Reuters report], including on military equipment, while Italy, Austria, and Spain do not want to upset commercial relationships with Iran.