The second televised presidential debate in Iran by the six candidates received a warning before it began.

"The debates should be on presidential issue[.] ... But we must avoid acts that rattle society," said Movahedi Kermani, the recent Friday prayer leader in Tehran, usually reflecting Supreme Leader Ali Khamenei's viewpoints.

These words referred to the 2009 uprising.  There is a belief in government circles that the audacious debate held prior to the 2009 presidential election sparked the follow-up uprisings.

Friday's debate followed the warning, and yet what the candidates were permitted to raise against each other in this limited scope of sanctioned topics was enough to bring shame upon one other.

"Last week the police discovered that Education Minister's daughter imported tons of Italian clothes and stored them in her house," said Tehran mayor Mohammad Bagher Ghalibaf in response to a question on education.

"This is while parents send their daughters to school in turns so that they can take turns in using their one set of clothes and shoes," Ghalibaf continued.

The next jab was from incumbent president Hassan Rouhani.

"When a member of the Majlis [parliament] went to Shiraz [southern Iran] to give a speech, your friends attacked him by throwing stones," he said.

Ebrahim Raisi, one of the most important figures involved in the 1988 massacre of 30,000 political prisoners, raised the issue of government fraud.  "The Teachers' Fund was looted, and officials stole 8 trillion tomans [equal to around $2.4 billion]," he revealed.

Another candidate, Mostafa Hashemitaba, a so-called "reformist" and former vice president, unveiled an upcoming crisis of colossal scale.

"It is estimated that 10 million migrants will be added to the city populations, and this will create a struggle between the different tribes ... threatening our internal security," he explained.

Moreover, he spoke of a previously unknown government scandal.

"We had an accord called Crescent due to which we were fined $14.5 billion," he said.

Mostafa Mirsalim, a former culture minister currently described as a conservative politician, called on Rouhani to talk about the $3 to $4 billion that was embezzled under the pretext of bypassing sanctions and to shed light on the fate of this huge amount of money.

He continued his attack on Rouhani, asking why he lied about the country's economic growth rate and why he didn't explain that 6% of the 8% in economic growth results from oil revenue.  International Monetary Fund estimates show that Iran's non-oil revenue remains at 0.9%.

Rouhani and his deputy showed restraint in this debate.  After the debate, Rouhani's adviser Hesameddin Ashena revealed the entire regime's fear of uprisings.

"In today's debate, Rouhani was worried and didn't want the debate to be a shock to society," he said.

Mohammad Amin (@EconomieIran) is a senior research fellow for the Paris-based Fondation d'Études pour le Moyen-Orient (FEMO), or the Foundation for the Study of the Middle East.  He has written several books and essays about the ruling theocracy, the transformation of Iran's political economy under the presidency of Mahmoud Ahmadinejad, and the rise of Islamic fundamentalism in the Middle East.