Demonstrators have set themselves on fire to protest against the arrests
Seven Iranian exiles have been placed under judicial investigation for alleged links to terrorism, as part of a large-scale French crackdown on Iran's opposition based in France.
An examining magistrate ordered the members of the Iranian People's Mujahedeen (MKO) movement to be investigated for "conspiring with a terrorist organisation", judicial officials said.
They were among 17 detained Iranian opposition supporters - including MKO leader Maryam Rajavi - who appeared before anti-terrorist judges in Paris.
About 200 people from the MKO were arrested in a crackdown by French police over recent days. The 17 held in detention were being questioned over alleged plans to attack Iranian embassies across Europe.
Security around the court was heavy in case supporters of the group tried to set themselves alight - as happened several times last week.
The BBC's Caroline Wyatt in Paris says Maryam Rajavi begged her followers not to harm themselves and most were demonstrating near the opposition group's headquarters in Auvers-Sur-Oise on Saturday.
At least 40 Iranian exiles are in their third day of a hunger strike and say they will continue until Maryam Rajavi and the others are released.
Military wing disarmed
Iran has welcomed France's actions against the group, which seeks the overthrow of the Islamic regime.
The MKO has been classified as a terrorist organisation by the United States and the European Union, although it maintains offices in several western European cities.
The group's military wing was disarmed by occupying US forces in Iraq in May.
The French Government said it is trying to stop the group from expanding its operations in France.
Interior Minister Nicolas Sarkozy said earlier the MKO "recently wanted to make France its support base, notably after the intervention in Iraq".
"We cannot accept that," he added.
The head of France's domestic intelligence service, Pierre de Bousquet de Florian, said the group was "transforming its Val d'Oise centre [near Paris] ... into an international terrorist base".
Maryam Rajavi is the wife of the group's leader, Massoud Rajavi. His brother, Saleh Rajavi, is also among those held.
Ten MKO supporters have set fire to themselves in European cities in protest at the raids at various sites in the north and west of Paris.