The CEO of WPP told The Guardian that he had heard rumours of jury members pressured into voting for selected entries and dismissing quality pieces of work from the judging process without due cause.
Dan Johns, CEO of Ikon and a media juror has also spoken up, telling B&T that the best work was not rewarded and that he and fellow jurors were planning on raising concerns over the voting process with Cannes chairman Terry Savage.
B&T also reports that while refusing to confirm if a complaint had been made, Savage had said that a review of the judging will take place once the festival is over.
The jury in question was chaired by Mainardo de Nardies, the chief executive of OMD Worldwide and Manning Gottleib OMD won the Grand Prix award for a Google Campaign.
In response to the article in the Guardian, Kassaei turned the tables on Sorrell accusing WPP judges of strategically shooting down Omnicom entries.
Clarifying that he was not speaking on the behalf of the Omnicom Group but only for DDB, Kassaei said that Sorrell should choose his words carefully because WPP was "briefed to kill Omnicom ideas."
"I have since been notified by no fewer than 12 jury members that people from other holding companies this week are being briefed to kill Omnicom, especially BBDO, DDB and TBWA, this is a fact.
"I don't remember that kind of intensity that it's happening this year, ever happening before. Maybe it's because Omnicom is dominating the industry and WPP had a problem chasing us and striving to be on the same level with us. Either you are a creative minded company based on your creativity and tradition or you're trying to buy creative.
"What differentiates Omnicom from WPP is the creativity and innovation. I would respect them if they did the better work. Just look at the objective facts, in the media category, WPP is doing better than Omnicom, so accusing use that we're playing silly games is not right."
He added that he had no reason to complain as so far this year has been the best for DDB result-wise. Instead he's speaking up because it angers him to see the integrity of the festival compromised, but so he's not misunderstood, he's choosing to speak ahead of the Film, Film Craft, Branded Content & Entertainment, and Titanium and Integrated Lions Awards tomorrow night so as not to be misunderstood.
"This festival is about defining the most important standards and set the bar for creative work in the world, if it's not fair and objective we have a problem, one that affects the industry, client and future talent. What kind of message are we sending?" asked Kassaie. "I'm especially worried about the signals we're sending young talent and the conclusions they will draw from the work awarded."
When asked what he felt Cannes Lions should do, Kassaie said the organisers should react very swiftly. "Every category should be under review for next year. Jury members should be clear about the integrity and responsibility they have and realise it's not about politics but about awarding the best of the best."
He added that DDB was "honestly and seriously" thinking about dropping participation in the Cannes Festival in future if these issues were not addressed. "We won't be part of the festival anymore, if it doesn't recognise the best work we have no reason to be here," said Kassaie.
Mark Tutssel, global CCO of Leo Burnett declined to comment on the veracity of either party's accusations without hard facts. "There are campaigns that have done well in other awards that have been suspicious in their absence, which has been igniting rumours. But the leadership of Cannes are professionals to operate with the utmost integrity and can be relied on to stamp out the problem."
From all he's heard,Tham Khai Meng, worldwide CCO of Ogilvy has done a "fine job" as jury president of Film and Press Lions. "The juries have said independently that he's done a fantastic job, that he's been fair and given each entry the time needed to be evaluated correctly," said Tutssel.
He does recommend that the festival's organisers do their best in future to "curate juries in a way that represents a cross-section of groups of networks that really draws upon the four corners of the world."
"I'd hate, really hate for this to tarnish something that's pure and beautiful and hugely beneficial to the industry," concluded Tutssel.
According to Campaign UK Kassaei’s comments have the full support of Keith Reinhard, chairman Emeritu of DDB Worldwide, who said, "I have to agree with everything Kassaei has said."
Campaign UK also reported that WPP declined to respond to Kassaei's comments.