CANNES, France — Even outside the Palais, the applause and cheers for Iranian director Mohammad Rasoulof was deafening.

An outspoken critic of the Iranian regime, Rasoulof was at the Cannes Film Festival to debut “The Seeds of the Sacred Fig,” a thriller about the family of a government worker in Tehran that descends into a terrifying web of mistrust and paranoia, mirroring the circumstances created by the country’s oppressive dictatorship. It’s a film Rasoulof had to complete in secret while on the run after being sentenced to eight years in prison, plus flogging and the confiscation of his property, by Iran’s Revolutionary Court for “security” violations. The sentence, Rasoulof’s lawyer wrote, was essentially for “signing statements and making films and documentaries.”