The trials of an Iranian political commentator and a French teaching assistant are set to resume in Tehran.
Saeed Leylaz and Clotilde Reiss were arrested along with hundreds of other people after Iran's disputed presidential elections in June.
Iran has accused Reiss of spying, while Leylaz was arrested days after he said that the re-election of Mahmoud Ahmadinejad as president would isolate Iran.
If found guilty, the defendants could face lengthy prison sentences.
Reiss has reportedly been living inside the French embassy in Tehran, having been released on bail at a Revolutionary Court hearing in August.
Patrice De Beer, a political analyst and a former editor of Le Monde, said that Reiss's arrest and trial have made the front pages of French newspapers in recent weeks.
"French president Nicolas Sarkozy took charge personally of all efforts to have her released - he called on Syrian president [Bashar] al-Assad to intervene," he said.
"Those negotiations ended with her being allowed to be released on bail. But the fact that she is going on trial and that the Iranian authorities have not accepted to guarantee that she will not be [sent] to jail have created a new tension."
De Beer said that many French people considered Reiss's arrest and trial to be politically motivated.
"Think about this 24-year-old woman - she is just out of university, she sees something that is rocking Iran and which is fascinating all Iranians," he said.
"She takes a few pictures, she looks around and witnesses what happens and she sends the pictures through her cellphone. Any youngster would do that, in any country, about anything that is very important.
"It looks to the French public and the French government like hostage taking in retaliation for the fact that the French government has a tough attitude on the Iranian nuclear problem."
Source: Al Jazeera