His comments in the documentary directed by Evgeny Afineevsky has been described by observers as his clearest remarks yet on gay relationships.
“They are children of God and have a right to a family. Nobody should be thrown out or made miserable over it.
“What we have to create is a civil union law. That way they are legally covered.”
He added that he “stood up for that”, apparently referring to his time as Archbishop of Buenos Aires when, although opposing same-sex marriages in law, he supported some legal protections for same-sex couples.
The film Francesco, about the life and work of Pope Francis, premiered as part of the Rome Film Festival.
As well as the Pope’s comments on civil unions, the film also shows him encouraging two gay men to attend church with their three children.
Pope Francis’s biographer, Austen Ivereigh, told the BBC he was “not surprised” by the latest comments.