Iranian foreign ministry spokesman, Dr Hamidreza Assefi, on Sunday described negotiations held in Paris between Iran and the Europe as complex and difficult yet constructive and progressing. At the Paris meeting which lasted more than 20 hours, considerable progress made towards reaching a preliminary agreement, he said. At the talks efforts were made to talk about and take into consideration the interests of both sides so that an agreement acceptable for the two sides could be reached between them, he added. The outcome of the talks and the understandings reached during the negotiations will be put at the disposal of the authorities of the Islamic Republic of Iran and the three European countries (France, Britain and Germany), he went on to say.