Thirty-six French production companies have issued an open letter urging ad agencies not to pitch with their own production units if they have invited independent bids.
It follows the ongoing US Department of Justice investigation into whether agencies are rigging production bids to favour their own divisions.
The letter said: "We reiterate our opposition to a system wherein agencies become both judge and jury as
regards certain competitions and, as such, lose the impartiality required for our sector to function effectively.
"This authoritarian, adversarial and non-transparent system has engendered practices which we deem
anti-competitive and which threaten the richness and diversity of French advertising productions."
The German producers association, Produzentenallianz, has also refused to compete against agency production teams. The alliance of 240 companies will include a statement in their bid letters to confirm their stance.
In the US, the Association of Independent Commercial Producers has recommended its members include similar information in bid letters. The Commercial Producers Association in South Africa has done the same.
Steve Davies, chief executive of the Advertising Producers Association, said worldwide reaction reinforces the APA’s call for stricter UK guidelines.
In January, 84 UK production companies signed a letter to say they refuse to be part of a system in which agencies invite external bids for production work they are considering pitching themselves.
Davies said: "We can see from the reaction to this around the world that this is just wrong – an agency inviting independent bids, bidding itself and choosing the winner.
"For the sake of the integrity of the ad business and, crucially, to maintain the confidence of advertisers in its integrity, the big ad groups – WPP, Omnicom, Publicis, etc. – should announce that they bid won't independent cos when they are contemplating doing the work themselves."