France said on Sunday its ambassador to Iran would not participate in an online business forum in Tehran this week, in a growing row between Iran and European nations over the execution of Iranian dissident journalist Ruhollah Zam.

Other envoys from Germany, Austria and Italy were also cancelling their involvement in the Dec 14 event, the French Foreign Ministry said on Twitter. At the foot of its tweet, the ministry ran the hashtag #nobusinessasusual.

In a separate statement, organisers of the Europe-Iran business forum later said they were postponing the event...