The demonstration, organized by the National Resistance Council of Iran (NRCI), was intended to protest a recent wave of executions in Iran and was expected by organizers to attract as many as 100,000 participants.

In an order issued on Thursday, Paris police said the event posed a serious security risk given the “particularly tense national and international context.” Authorities warned that confrontations between groups holding opposing political views could disrupt public order, especially because the planned route passed near government buildings and diplomatic missions.

The NRCI said the prohibition was communicated after business hours on Thursday and described the reasons given by authorities as “bogus.” The group has filed an emergency legal challenge seeking to overturn the ban before the planned gathering.

Organizers suggested the decision may have been linked to diplomatic contacts between France and Iran, noting that the cancellation came hours after a telephone conversation between French Foreign Minister Jean-Noel Barrot and his Iranian counterpart.

France’s Foreign Ministry rejected that assertion, stating that Barrot neither raised the planned demonstration nor requested its cancellation during the call.

The NRCI serves as the political wing of the People’s Mujahedin of Iran (PMOI), also known as the MEK, a group designated as a terrorist organization by Iran’s government.

The organization has staged numerous demonstrations in Paris over the years, including rallies linked to anti-government protests in Iran and recent regional tensions involving Tehran.

French authorities highlighted concerns that competing Iranian diaspora groups, many of which maintain deep political disagreements, could come into conflict during the event.

The planned march was intended to draw attention to executions carried out in Iran during the recent conflict involving Tehran, Israel and the United States.

Human rights organizations have reported that more than 40 people have been executed in Iran since the outbreak of the conflict, including individuals allegedly connected to anti-government protests.

Iranian authorities have also carried out executions involving individuals accused of links to banned opposition movements, including the MEK, as well as outlawed Kurdish and Sunni Baluch organizations.

The court challenge filed by organizers is expected to be considered on an expedited basis ahead of the scheduled date of the rally.