Web and media agency: agency buying, advertising space, VAT and revenue recognition (2026)

Quick answer. A web and media agency separates its own services (creation, consulting, development) — which are its turnover, subject to VAT at the standard 20% rate — from advertising space bought on behalf of the advertiser. That media buying falls under the Sapin law (Law no. 93-122 of 29 January 1993), which requires a written mandate: sums rebilled at cost flow through third-party accounts and are not the agency's turnover.

A web and media agency bills a wide range of services: website creation, campaigns, content, consulting, but also advertising space buying (display, social media, television, press). Each operation has a different accounting and tax treatment. The main source of error is to record as turnover sums that are merely flows managed on behalf of the advertiser.

At Hayot Expertise, we support communication agencies, studios and digital services companies. This guide sets out the right approach for an accountant for web and media agencies: qualify each flow, apply the right VAT, and recognise revenue at the right time.

In French, the word "régie" is confusing because it covers two different realities.

• "Régie" as a billing mode means a service billed on a time-and-materials basis, as opposed to a fixed fee or project. It is a way of remunerating your own service.
• An advertising sales house (régie publicitaire) means the activity of selling advertising space on behalf of media owners.

When an agency buys advertising space for an advertiser, it usually acts as an agent under a mandate. This is the case that triggers the Sapin law obligations. The agency's own revenue (campaign management or consulting) must be distinguished from the price of the space, which economically belongs to the advertiser.

Law no. 93-122 of 29 January 1993, known as the Sapin law, strictly governs media buying carried out by an intermediary. Its rules, extended to every medium (including digital) by law no. 2015-990 of 6 August 2015, require:

1. A written mandate between the advertiser and the agency for any media buying or advertising service carried out in its name.
2. Transparent remuneration: the mandate details the services and the agent's remuneration.
3. Transparency of rebates: any rebate or pricing advantage granted by the seller (the medium or the sales house) must appear on the invoice sent to the advertiser and cannot be kept by the intermediary, unless expressly stated in the mandate.
4. A ban on hidden advantages: the agent may receive no payment other than that from its principal, nor any remuneration or advantage from the seller.

In accounting terms, under a mandate, sums paid to the medium and rebilled at cost to the advertiser flow through third-party accounts: they do not enter the agency's turnover. Only the agent's remuneration — a management commission or fee — is income. This third-party-account logic is close to escrow, which we describe in our article on escrow accounting in real estate agencies.

For business customers established in another State, the general territoriality rule places the service at the customer's location (article 259, 1° of the General Tax Code): the agency invoices net of tax and the customer accounts for the VAT. For European Union customers, a European services declaration accompanies these operations. We detail these mechanisms in our article on the VAT of intra-community services.

When revenue becomes earned depends on the billing mode:

• Fixed fee or project: revenue is recognised on a percentage-of-completion basis. Advances received but not yet earned are booked as deferred income.
• Time-and-materials: revenue is recognised as the work is performed, based on billed time.
• Subscription or recurring service: revenue is spread over the service period and attached to the relevant financial year.

This discipline avoids artificially inflating a year with advances or media buying. To go further on the fixed-fee versus time-and-materials trade-off, see our analysis on revenue recognition for fixed fee and time-and-materials and, for independents, on the independent consultant and daily rate.

• Rebilling of costs and subcontracting. When an agency subcontracts part of a project (developer, motion designer), the service rebilled in its name is turnover, to be distinguished from media buying under mandate.
• Content creators and influencers. An agency paying creators handles specific flows, covered in our guide on content creators and influencers.
• Media buying outside a mandate. If the agency buys space on its own account and resells it in its name, it is no longer an agent: turnover then includes the price of the space, which radically changes its ratios.

• Do not confuse third-party flows with turnover. Recording media buying as income inflates turnover and distorts margin.
• Formalise the mandate. The absence of a Sapin-compliant written mandate exposes you to penalties and complicates audits.
• Trace rebates. Any rebate from the medium must be returned to the advertiser, unless expressly stated otherwise.
• Check VAT territoriality. A wrongly qualified service to a foreign customer leads to VAT wrongly collected or omitted.
• Anticipate e-invoicing. Receiving becomes mandatory on 1 September 2026 for all businesses.

Recently, a fast-growing digital agency contacted us because its gross margin looked abnormally low. Analysing its accounts, we found that media buying carried out for its advertisers was recorded as turnover, and its cost as expenses. The reported turnover was thus inflated by several hundred thousand euros of flows that did not belong to it.

We reclassified these operations as third-party accounts, in line with the Sapin law mandate logic, and isolated the agency's remuneration alone. The real turnover emerged, the margin returned to a coherent level, and reporting became readable for the partners and the bank. Along the way, we secured the written mandates with the advertisers. An agency's billing structure is not just an accounting detail: it drives how performance is read and financial credibility.

Hayot Expertise advice. Map your flows: own services, media buying under mandate, rebilling. Put in place Sapin-compliant written mandates, a chart of accounts that isolates third-party flows, and a clear revenue recognition policy (fixed fee, time-and-materials, subscription). Dedicated accounting support for agencies and tax advice give you sincere turnover and reliable indicators.