Media agency fee transparency: why I have clients pay their media budgets directly, and what France's Sapin law still fails to fix in digital advertising.
The first question I ask a founder who shows me a media plan is not "what is your CAC?". It is "who pays the media owner?". If the answer is "the agency, and they rebill us", I already know where to look. Not because the agency is dishonest. Because as soon as media money flows through the intermediary's account, nobody can say with certainty what the space cost and what the advice cost. At Jour de Chance, media budgets are paid directly by the client, to the media owners and the platforms. I invoice my work. Two lines, two invoices, two issuers. Here is why.
Media agency fee transparency: what the Sapin law already settles
France has one of the strictest frameworks in the world on this, and it is more than thirty years old. Law no. 93-122 of January 29, 1993, known as the Sapin law, sets three rules every advertiser should know by heart. Article 20: an intermediary can only buy advertising space on behalf of an advertiser, under a written agency mandate, and any discount granted by the seller must appear on the invoice issued to the advertiser. Article 21: the agent cannot receive "any remuneration or benefit whatsoever from the seller". Article 23: the seller reports directly to the advertiser, within one month of the campaign airing, on the conditions in which it was delivered.
Decree no. 2017-159 of February 9, 2017, in force since January 1, 2018, extended that reporting obligation to digital advertising: dates and placements, total campaign price, unit price of the space invoiced.
On paper, everything is settled. In TV, radio and out-of-home, it works rather well: the sales house sends you its invoice, you see gross, discounts and net. But the law guarantees that you see the invoice. It does not require you to pay it yourself. And that gap is where the fog settles.
Where it leaks: digital and buy-and-resell
As early as July 2013, the French government report "Loi Sapin et publicité sur Internet" (Lallement, Serris, Varenne) described the problem: in real-time buying, intermediaries place themselves in the middle of the transaction between seller and buyer, some trading desks set themselves up as sales houses so as not to act as agents, and "an intermediation cost above 50% is plausible". Thirteen years later, the measurements have confirmed the order of magnitude.
- ISBA and PwC, United Kingdom. First study in 2020: 51% of advertiser spend reaches publishers, and 15% cannot be attributed to anyone. Second study in January 2023, after three years of pressure: 65% reaches publishers, the unknown drops to 3%. When people look, it improves.
- ANA, United States, December 2023. Across the campaigns of 21 major advertisers, 36 cents of every dollar entering a DSP actually reaches the consumer. The average campaign runs on 44,000 websites. Estimated efficiency gain: $22 billion on an $88 billion market.
- ANA and K2 Intelligence, June 2016. When the agency buys on its own account and resells to its client, the markups observed range from 30 to 90% in some cases.
That last point has a name today: principal media. The agency is no longer your agent, it is your seller. And it is growing. On March 19, 2026, the ANA published a survey of 114 client-side marketers: 58% used principal media in the past year, up from 47% in the previous wave. And 90% worry that their agency's recommendations on that inventory are not primarily in their interest. It was 79% in 2024. On the control side, Ebiquity (Media Agency MSA Transparency Report 2025, 83 leaders surveyed) notes that nearly half of advertisers can only audit the signing agency, not the group's affiliates or trading desks, and that 40% have run no contract compliance audit in 24 months.
I am not putting the big networks on trial. I am describing a mechanism: when the person advising you earns more depending on what they get you to buy, you no longer have advice, you have a salesperson.
What direct payment changes, concretely
You see the net price, with nothing to reconstruct. The media owner's invoice is in your name and you settle it. Meta's or Google's comes out of your ad account, on your payment method. There is no "media space" line on my invoice, so nothing to check on it.
My interest does not depend on what I get you to buy. We take no commission from media owners. So I can recommend cutting a channel, moving a budget, or spending less. For Comptoirs de la Bio, isochrone targeting halved the budget compared with leaflets, with a 100% tracked setup. Halving a budget is a recommendation that a commission model makes expensive for the person giving it.
Your accounts stay yours. On social and online video, insist that the ad account be opened in your company's name, with the agency holding partner access only. History, pixel, audiences, what the algorithm has learned: all of it follows you the day you change provider. An account hosted by the agency is an asset you paid for and do not own.
Your cash does not fund mine. No call for funds three weeks before airing, no budget sitting in an account that is not yours. For a scale-up counting its months of runway, that is not a detail.
The five questions to ask your media agency
1. In whose name are the media owners' and platforms' invoices issued, and who pays them? 2. Who owns the ad accounts and the data inside them? 3. On each line of the plan, are you an agent or a seller? 4. Do you receive anything from media owners or platforms: year-end rebates, free space, partner programmes? 5. Can I audit, including your affiliates and your trading desk? An agency comfortable with its model answers in two minutes. The others send you a deck.
The objections, and what I think of them
"It means more paperwork." Yes. Several invoices instead of one, and supplier accounts to open. That is the price of clarity, and your CFO will always prefer three clear invoices to a single one that has to be picked apart.
"Big groups get better prices thanks to volume." Sometimes true, and it should be said. In the 2026 ANA survey, 76% of advertisers cite lower costs as the main benefit of principal media. But a low price on inventory the agency has an interest in moving is not necessarily the inventory you need. A CPM is judged on what it produces, not on the discount displayed. If your agency offers this kind of buy, ask for the alternative under a standard agency mandate and compare the two on results.
"And how do you make a living?" From fees, written in black and white in the contract. And when I want to tie my remuneration to your success, I prefer equity to commission: that is the logic of media for equity, where part of the fees is converted into shares. There, my interest is that your company is worth more, not that you spend more.
What I tell founders
You do not need to suspect your agency. You need a setup where the question does not arise. Paying your media owners directly does not make a media plan better. It makes its cost visible, and it guarantees that the person telling you "put 80,000 euros into TV" earns nothing more if you put in 120,000. At 10,000 euros a month or at a million, the rule is the same.
If you have doubts about what your budget actually funds, our free audit starts there: we go through your invoices, your accounts and your contract, and tell you where every euro goes. And if you are running a pitch, the guide to choosing your media agency gives you the right criteria.
