Nicolas Henin (centre) and Pierre Torres (right), were greeted by French President Francois Hollande after their release last year
A French hostage, held for 10 months by the British militant known as "Jihadi John", has been speaking to the BBC about his time in captivity, and his interactions with his jailors.
Nicolas Henin was marking the publication of a children's book written in captivity with fellow French journalist Pierre Torres.
The book, Will Daddy Hedgehog Ever Come Home?, was written for Henin's five-year-old daughter, and is published this week. It was written by the two journalists in secret at night, on a scrap of cheese wrapping.
Henin says the story grew out of a game to relieve the boredom of captivity, devised by the British aid worker David Haines, who was later killed by his captors.
"The aim was to say which animal portrays you best," Henin told me. "I spoke about being a hedgehog. I liked the idea of [having] good protection - even though the protection of a hedgehog is totally stupid."
To protect himself in captivity, he says, he used the same "totally stupid" technique: "I would make [myself into] a ball."
But then, in terms of protection, "nothing ever really worked. As a hostage, you're just a puppet."
He also described the discussions between the prisoners and their Islamic State captors.
Such contacts were often important to secure vital food and medicine. But they also revealed jarring details about their captors' backgrounds and interests.
"I noticed that these jihadists have little to do with the local culture - Arab or Muslim culture - they are children of our societies.
"They speak our language, they have the same cultural references we do. They watch the same movies as us, play the same video games our children play. They are products of our culture, our world."
They watched everything, Henin says, "from the Teletubbies to Game of Thrones."
BBC News - Islamic State ex-hostage Henin: Asking for pity is stupid