Since May 2024, France has had a public standard for sustainable web design and digital services in general: the RGESN, published by the telecoms regulator Arcep and the media regulator Arcom, together with the environment agency Ademe. It is not one more official text: it is a grid of 78 verifiable criteria, written to be audited rather than commented on. Rather than simply cite it, this article turns it into concrete decisions for a business website, and says plainly which ones do not concern you.
What the RGESN is, in plain terms
The Référentiel général d’écoconception de services numériques, the general framework for the sustainable design of digital services, was published on May 17, 2024 by Arcep and Arcom, in association with Ademe and with the support of the Dinum (the state’s digital directorate), Inria (the national research institute for digital science) and the Cnil (the data protection authority). It stems from the law of November 15, 2021 on reducing the environmental footprint of digital technology, known as the REEN law, which had entrusted the regulators with defining this shared grid.
It runs to 78 criteria in nine families, from strategic choices down to the line of code.
| Family | What it examines |
|---|---|
| Strategy | Environmental goals, governance, in-house skills |
| Specifications | Real usefulness of features, intended lifespan of the service |
| Architecture | Technical structure, lean data flows, reversibility |
| UX and UI | Short journeys, no needless prompts, readability |
| Content | Weight of images and videos, formats, editorial life cycle |
| Frontend | Requests, scripts, fonts, browser cache |
| Backend | Server processing, stored data, logs |
| Hosting | Energy efficiency, provider commitments, location |
| Algorithms | Computing cost of automated processing, lean models |
The overall logic comes down to two principles. Reduce at source rather than offset, first. Then extend the life of the hardware, which is the most original contribution of the text: a site that is too heavy forces people to replace their phones, and that manufacturing weighs far more than the electricity used to display it. The practical consequence is that the most structuring criterion in the framework is not technical at all. It consists of asking, feature by feature, whether it genuinely serves anyone.
Who is actually affected
Let us give a straight answer: the RGESN is not enforceable against a private company. It is a voluntary framework, and nobody is going to come and inspect your brochure site. The picture grows more nuanced as soon as you look at public bodies and public procurement.
- Municipalities and inter-municipal bodies with more than 50,000 inhabitants had to adopt a responsible digital strategy by January 1, 2025, under the REEN law. The sustainable design of digital services is explicitly part of it.
- Central government departments apply the approach under their inter-ministerial roadmap, and the framework serves as the common base for public development contracts.
- Private companies have no direct obligation, but the subject reaches them on the rebound: sustainable design clauses in public tenders, supplier questionnaires from large clients subject to sustainability reporting, responsible purchasing policies.
In other words, a small business has nothing to fear and a good deal to gain. If one day you answer a public tender, or if you supply a group subject to sustainability reporting, the question will land, and it is better to have the answer already written down. For the exact state of the law, read the source rather than the interpretations: the official page of the framework and the Arcep dossier on the environmental footprint of digital technology, both in French, are the authority.
The ten criteria that change a brochure site the most
Of the 78 criteria, around thirty concern complex application services and do not apply to a business website. Here are the ten that produce most of the result, with their measurable effect.
- Remove what serves nobody. A carousel of six visuals loads six images for a single one that actually gets looked at. Taking it out routinely lightens a home page by 800 KB to 1.5 MB, and improves conversions rather than the reverse.
- Limit the number of requests. A lean brochure site stays under forty requests per page. The same site built blind with a visual page builder and fifteen plugins routinely demands 120 to 200.
- Match image weight to the display context. A 4,000-pixel photograph shown in an 800-pixel block carries twenty-five times too much data. Modern formats, several declared sizes, and a realistic target: under 150 KB per content image, under 300 KB for a banner.
- Ban autoplaying video. A background video on the home page weighs more than the whole of the rest of the site put together, and cuts out on half of all mobiles.
- Cut down the fonts. Two families, two weights, in WOFF2 format, with a limited character subset. Each additional weight adds 20 to 40 KB loaded before the text appears.
- Cache properly. A server-side page cache, and long browser cache headers on versioned files. A returning visitor should not have to download again what has not changed.
- Reduce third-party scripts. Every tracker, every share button, every interactive map opens connections to other domains. Count them: three are almost always enough, and twelve are often what you find.
- Guarantee that it works on old hardware. This is the most neglected criterion, and the truest to the spirit of the text. Test your site on a five-year-old phone, on a throttled network. If it remains usable, you are forcing nobody to change their device.
- Plan for the end of life of your content. An obsolete page that nobody reads goes on being crawled, backed up, migrated and indexed. Unpublishing or archiving is part of sustainable design, on the same footing as compressing.
- Measure before you claim. A figure taken before the work and after the work is worth a thousand adjectives. It is also what the sustainable design declaration requires.
These ten points do not require rebuilding the site. They can be dealt with on an existing site, in order, and they carry on naturally when you start again from a sound base to build a light, fast site.
Sustainable web design and accessibility go together
Here is the angle that almost nobody picks up on: nearly every sustainable design decision improves accessibility, and the reverse is true too. A lighter page displays faster on modest hardware, and so stays usable for people equipped with older devices. Content that can be read without running a script stays readable for a screen reader. Well-controlled contrast serves visual restraint as much as legibility. The absence of forced animation respects both the battery and people who are sensitive to motion.
So there are not two projects to run but one, read through two grids: the RGESN on one side, the general framework for improving accessibility on the other. We already publish our accessibility statement, and bringing the two approaches together is what speaks most to public buyers and committed business owners alike.
Measuring without fooling yourself
Page footprint calculators are useful for raising awareness, debatable for steering by. Two tools run on the same page often give results far apart, because they rest on different assumptions: the electricity mix chosen, the lifespan attributed to devices, the share of traffic served from a cache, the average viewing time. None of these assumptions is wrong; none is verifiable on your site.
Track four stable indicators instead, ones you can read yourself and compare over time:
- The weight transferred by a page, in kilobytes, on a first visit and on a repeat visit.
- The number of requests and the number of third-party domains contacted.
- The server response time, which betrays under-sized hosting better than any overall score.
- The share of content actually viewed, taken from your statistics: the pages nobody ever sees are the richest seam of savings.
The golden rule: compare your site with itself, six months earlier, and not with a competitor’s whose scope you do not know. Website carbon footprint: how to measure and reduce it details the available tools and their limits.
Our position: what we apply
Our choices predate the framework, which spares us having to bring ourselves into line with a text. Pages built to stay light, images converted and sized for real use, two font families at most, third-party scripts cut to the strict minimum, hosting that is documented and sized for real use. The most useful sorting, though, does not happen in the code: it happens at the scoping stage, when we ask what each requested block is for. A feature that is never written consumes nothing, never needs updating and never breaks down.
On hosting, our logic is the same as the one set out in our article on choosing hosting that is genuinely low impact: what counts is what you avoid consuming; offsetting comes only afterwards, and never instead. This approach flows through the whole design of our sustainably built website plans.
Where to start if you are starting from scratch
Five actions fit into a single working day and already cover a good share of the applicable criteria.
- Measure the current state of your three most visited pages: weight, requests, third-party domains. Write the figures down and date them.
- Remove the useless third-party scripts. The tracker from a campaign that ended two years ago, the widget for a social network you no longer feed.
- Reprocess the five heaviest images, in the right format and at the right size. That is often half the gain.
- Switch off autoplay and permanent decorative animations.
- Document what has been done, in a sustainable design declaration published on the site: criteria adopted, criteria set aside and why, indicators tracked, next actions.
This last step is the one everybody skips, and yet it is the only one that turns an intention into proof. What gives an approach its worth is its continuity, not its initial perfection. For the everyday habits that carry the approach through on the team side, see 12 habits for a lighter web.
Complying with this framework means building it in from the design stage, as an Ocean Friendly web agency does.
Frequently asked questions
Is the framework compulsory for my business?
No, not directly for a private organization: the RGESN is voluntary. It becomes binding through public procurement and through the supplier questionnaires of large clients, where it increasingly serves as the evaluation grid.
Is a sustainably designed site less attractive?
No. It is stripped of the superfluous, which generally improves readability and the conversion rate. The constraint bears on weight and on the number of prompts, not on graphic quality.
Do you have to rebuild your site to comply?
No. A large share of the criteria that apply to a brochure site can be dealt with on the existing one, through successive adjustments: images, third-party scripts, fonts, cache, obsolete content. A redesign is only useful if the technical foundation is itself the problem.
How do you prove your approach?
By publishing a sustainable design declaration on the site: criteria adopted, criteria set aside with the reasons, indicators tracked and an improvement plan. It is this document, not a logo, that is asked for in a tender.
What to remember
Digital sobriety is not a garnish of good conscience; it is a design method that produces sites that are faster, more accessible and cheaper to maintain. The RGESN has the merit of making it verifiable. Start by measuring your three main pages this week: without a starting figure, no progress will ever be demonstrable.
Also worth reading: How to spot an Ocean Friendly web agency
