Protesters yelled "extinction" and "we won't have a future" as they were carried away by French police.
Festival organizers had originally extended an invitation to the group to participate in the Lions in an official capacity, but where ultimately denied by the French authorities.
French authorities arrested the first batch of 14 Extinction Rebellion activists on Wednesday, after the group staged a demonstration at the Palais.
Protesters dropped a banner with the words “Tell the Truth” from the Church of Our Lady of Esperance which overlooks the Palais before blocking the main entrance to the event a few hours later. They linked arms and sat on the steps chanting “We are in the 6th mass extinction," and "If we don’t act now, the biodiversity on which we depend will collapse.”
According to a spokeswoman for the group who talked to Ad Age, the protesters are "mostly French" although they include some of the group who cycled down from London earlier in the week. Police arrested 12 people for blockading the Palais and arrested two for handing out flyers. They were fined and released within half an hour.
Extinction Rebellion are demonstrating against "the business as usual mentality and the idea that talking about climate change can be profitable and not addressing the issue, and the fact that they guide consumer choices, face on," she said, adding: "It isn't a case of blaming individuals for not doing enough, but encouraging the industry to be on the right side of history. "The group almost had a chance to appear at the Festival officially; members met with the CEO of Cannes Lions, Phil Thomas, before the Festival started. Thomas told Ad Age he received a phone call from the group last week, having earlier reached out to them, and met with four of them, including William Skeaping, a former employee of McCann London, who is playing a key role in the Cannes activity. "We had a glass of rosé together, and I liked them very much," he says.