France’s top film institutions have joined to launch an international petition to free the six Iranian filmmakers jailed since Sept. 18 by Iran’s authorities.

The petition was initiated by the Cannes Film Festival, the French Cinematheque, the French Directors Guild, the Guild of Authors, Composers and Directors, sales company Wide Management and distributor Kanibal Films.

They join a growing number of institutional protesters that include the Vancouver Film Festival and Germany’s Mannheim-Heidelberg fest.

Within a day of the broadcast of a docu about Iran’s leader, Ayatollah Ali Khamenei, on BBC Persia, the filmmakers — Mojtaba Mirtahmasb, co-director of Jafar Pahahi’s “This Is Not a Film,” directors Nasser Saffarian, Hadi Afarideh, Mohsen Shahrnazdar, Shahnama Bazdar and producer Katayoun Shahabi — were accused of spying on the Iranian government for BBC Persia and imprisoned. The accusations sparked from various Iranian bodies, notably the Tehran Senate, the information and culture ministries, an Iranian news agency, the secret services, a dozen of Islamist students associations and Iranian television networks.

In a release, the French institutions said the families of the filmmakers had been banned from visiting them in prison.

Wide Management’s founder Loic Magneron, who owns international rights to “This Is Not a Film” and handles world sales, said his company was considering organizing a protest in Paris.

The House of Cinema in Iran also launched a call to free the imprisoned filmmakers, but the government immediately accused it of being a political party and denied it official recognition.

“This Is Not a Film” was recently released in France by Kanibal after opening at Cannes and playing Toronto, among other festivals. Clementine Hugot, sales agent at Wide Management, said the doc will also unspool at the Vienna Film Festival.

Mirtahmasb had his passport pulled on Sept. 5 at Tehran airport while on his way to France to promote the release of “This Is Not a Film,” depicting Panahi’s life under house arrest. Doc was shot on an iPhone and smuggled out of the country.

Panahi is appealing his six-year jail sentence and 20-year ban on filmmaking for his anti-government stance.