Once again, creative and media agencies dominated the Cannes Lions PR category, despite the festival's addition of a PR agency partner option and an increase in submissions from PR agencies.

Entertainment group Creative Artists Agency won the PR Grand Prix with partner agency Edelman for "The Scarecrow," an integrated campaign for client Chipotle Mexican Grill.

What is it: Following the success of its 2012 Cannes Grand Prix winner "Back To The Start," Chipotle and CAA Marketing developed a short film in which Chipotle took on Big Food in order to highlight its own sustainably-sourced ethos.

The campaign launched on YouTube with no paid media for the first four weeks. That was followed by a placement in a national newspaper and a social and PR push, as well as the launch of an interactive game and a mobile coupon meant to drive consumers to Chipotle restaurants.

Why it won: "It was the storytelling," said Renee Wilson, PR jury president for Cannes Lions and chief client officer at Publicis Groupe's MSLGroup. "The work was stellar. It was designed to really engage consumers in an emotional way on the Chipotle journey to creating a sustainable future."

She emphasized that the campaign was driven by PR and earned media, but had a number of integrated elements.

The jury: Ms. Wilson led a jury of 21 executives.

The jury deliberated from 9 A.M. to midnight, according to festival CEO Philip Thomas.

Controversy or clear winner: The jurors also called out Forsman & Bodenfors' Live Test Series campaign for Volvo Trucks.

"We saw a lot of videos and films that have gone viral," said Forsman & Bodenfors' Desiree Maurd, who was on the PR jury. "Live Test Series had both film craft and PR craft executed extremely well. It was really integrated in that sense." (She admitted she might be a bit biased.)

Hot topic at press conference: Entries for PR nearly doubled this year, making it one of the fastest-growing categories at Cannes. However, only a handful of PR agencies that entered work made the shortlist, even as more agencies entered. Last year, just over 20% of the entries in the category came from PR shops. This year, that number doubled, leading to a 40-60 split between PR agencies and other types of shops, like creative and media.

This year, for the first time, the festival added separate fields for the agencies that submitted and paid for entries and for their partner PR agencies.

"We've been talking a bit about the ad agencies or PR agencies that enter these awards," said Ogilvy PR's Ann Maes. "We feel that PR is not a discipline; it's a state of mind. It's bringing credibility to campaigns. Anyone can do that. We want to be awarding good work and work together in an integrated matter. We're all excited [ad agencies] have started to adopt our thinking."

"I'm not sure it does matter because of the blurring of the lines," added Ms. Wilson. "It's so collaborative."

Lions awarded: There were 13 Gold Lions, four of which came from the U.S. Most of the campaigns that won Gold Lions, such as "This is Wholesome" for Honey Maid and "Dallas Gas Station" for TNT, came from ad agencies. CAA's "Scarecrow" also won two Gold Lions, in addition to the Grand Prix.

Although both Edelman and IPG's Weber Shandwick partnered with entrant shops that won Gold Lions for their work, no PR agencies actually entered campaigns that won Gold Lions.

For more Cannes work highlights, tune into Creativity's "The Best of Cannes."