Question: What was the duration of the film-making ban on Panahi?
About the article "This Is Not a Film", section "Synopsis".

Candidate passages:
Closed Curtain () is a 2013 Iranian drama film by Jafar Panahi and Kambuzia Partovi.
It premiered at the 63rd Berlin International Film Festival on February 12, 2013 where Panahi won the Silver Bear for Best Script.
It was shot secretly at Panahi's own beachfront villa on the Caspian Sea.
Panahi stated that he began shooting the film in a state of melancholy but managed to recover by the film's completion.
"Closed Curtain" is Panahi's second film since his 20-year ban on filmmaking after 2011's "This Is Not a Film".
The film was selected as the closing film of the 2013 Hong Kong International Film Festival. 
In 2006 Panahi made "Offside".
In the film, a group of young Iranian girls disguise themselves as boys to sneak into Azadi Stadium to watch the World Cup qualifying football playoff game between Iran and Bahrain.
The film was partially shot during the actual game it depicts.
Since the 1979 Islamic Revolution women have been banned from attending football matches in Iran on grounds of rowdy and aggressive language, lewd behavior, and seeing men in shorts and short sleeve shirts.
At one point Mahmoud Ahmadinejad had wanted to repeal the law but was overruled by the ulema.
Panahi has stated "I use the football game as a metaphor to show the discrimination against women on a larger scale.
All my movies have that topic at their center.
This is what I am trying to change in Iranian society."
The film was inspired by an incident several years earlier when Panahi's daughter was refused entry to a football stadium but ended up sneaking into the stadium anyway.
Knowing that the film would be controversial, Panahi and his crew submitted a fake script about some young men who go to a football match to Iranian authorities in order to get permission to make the film.
However before they began shooting the Ministry of Guidance, which issues licenses for films to be shown publicly, told Panahi in advance that because of his past films they would not issue "Offside" a license until he re-edited his previous films.
Not wanting to miss the World Cup tournament, Panahi ignored the Ministry and began shooting the film.
As usual, Panahi cast non-professional actors for the film, and the group of young girls in the lead roles were mostly university students that Panahi found through friends who all were passionate fans of football.
The film was shot in 39 days and in order to move unnoticed through large crowds Panahi used digital video for the first time so as to have a smaller, more inconspicuous camera.
Panahi also officially listed his Assistant Director as the Director of the film so as to not attract the attention of the Ministry of Guidance or the Disciplinary Forces of Tehran, but towards the end of the films shooting a newspaper article about the making of the film listed Panahi as the director and both organizations attempted to shut the film down and confiscate the footage.
Only a sequence that takes place on a bus remained to be filmed so Panahi was able to continue filming without being caught.
The film premiered in competition at the 2006 Berlin Film Festival, where Panahi was awarded with the Silver Bear Jury Grand Prix.
Like "The Circle" and "Crimson Gold" before it, "Offside" was banned from being shown in Iran.
Panahi had already set up distribution for the film all over Iran and the film was predicted to break all box office records.
Two days after being banned and twenty days before the World Cup championship game, pirated DVD copies of the film became available all over Iran.
Panahi has stated that of his films "Offside" is "probably the one that people have seen the most" in Iran.
After the film's release a feminist protest group in Iran called the White Scarf Girls began showing up at football matches carrying banners that read: "We don't want to be Offside" Sony Pictures Classics, the film's U.S. distributor, wrote a letter to the Ministry of Guidance in Iran requesting that the film be shown for at least one week in its home country so that they could launch a campaign to nominate the film for Best Foreign Language Film, but the Ministry refused. 
Jafar Panahi (; born 11 July 1960) is an Iranian film director, screenwriter, and film editor, commonly identified with the Iranian New Wave film movement.
After several years of making short films and working as an assistant director for fellow Iranian film-maker Abbas Kiarostami, Panahi achieved international recognition with his feature film debut, "The White Balloon" (1995).
The film won the Caméra d'Or at the 1995 Cannes Film Festival, the first major award won by an Iranian film at Cannes.
Panahi was quickly recognized as one of the most influential film-makers in Iran.
Although his films were often banned in his own country, he continued to receive international acclaim from film theorists and critics and has won numerous awards, including the Golden Leopard at the Locarno International Film Festival for "The Mirror" (1997), the Golden Lion at the Venice Film Festival for "The Circle" (2000), and the Silver Bear for Best Director at the Berlin Film Festival for "Offside" (2006 ).
His films are known for their humanistic perspective on life in Iran, often focusing on the hardships of children, the impoverished, and women.
Hamid Dabashi has written, "Panahi does not do as he is told — in fact he has made a successful career in not doing as he is told.
"After several years of conflict with the Iranian government over the content of his films (including several short-term arrests), Panahi was arrested in March 2010 along with his wife, daughter, and 15 friends and later charged with propaganda against the Iranian government.
Despite support from filmmakers, film organizations, and human rights organizations from around the world, in December 2010 Panahi was sentenced to a six-year jail sentence and a 20-year ban on directing any movies, writing screenplays, giving any form of interview with Iranian or foreign media, or from leaving the country except for medical treatment or going to Hajj pilgrimage.
Whilst awaiting the result of an appeal he made "This Is Not a Film" (2011), a documentary feature in the form of a video diary in spite of the legal ramifications of his arrest.
It was smuggled out of Iran in a Flash-Drive hidden inside a cake and shown at the 2011 Cannes Film Festival.
In February 2013 the 63rd Berlin International Film Festival showed "Closed Curtain" ("Pardé") by Panahi and Kambuzia Partovi in competition; Panahi won the Silver Bear for Best Script. 
2010–present: further film career.
"This Is Not a Film" (2011).
In the middle of the controversy and court appeal, Panahi broke the ban imposed on him from making films and made the documentary feature "This Is Not a Film" (2011) in collaboration with Iranian filmmaker Mojtaba Mirtahmasb.
This film was made for €3,200 and shot on a digital camcorder and, partly, an iPhone.
It was shot in four days over a ten-day period in March 2011 and its title was inspired by René Magritte's painting "The Treachery of Images".
In the film, Panahi sits in his apartment making phone calls about his court case, watching TV news stories, interacting with his neighbors, talking about his past films and describing scenes from the film that he had begun shooting when he was arrested (much as he had described scenes from films to his sisters as a child).
Ten days before the opening of the 2011 Cannes Film Festival, "This Is Not a Film" was announced as a surprise entry into the festival.
It was smuggled out of Iran on a USB thumb drive that had been hidden inside a cake.
Panahi's wife and daughter attended the festival.
In December 2012 it was shortlisted as one of 15 films eligible for Best Documentary Feature at the 85th Academy Awards. 
Panahi is married to Tahereh Saidi, who he first met while he was in college when she was working as a nurse.
Together they have a son, Panah Panahi, born in 1984 and a daughter, Solmaz Panahi.
Panah Panahi attended the University of Tehran and in 2009 made his first short film, "The First Film", which was screened at the 2009 Montreal World Film Festival.
His daughter Solmaz studied theater in Tehran.