Web accessibility and SEO: the shared criteria and the obligations

Why an accessible site ranks better, what the law has required since 2025, and the ten criteria to check first

The essentials

  • The connection: Google reads a page the way a screen reader does; the accessibility criteria (alt text, a heading hierarchy, explicit links, semantic HTML) are also comprehension criteria for the engine.
  • RGAA: France's general accessibility framework, version 4.1, 106 criteria, mandatory for the public sector and for companies with revenue above €250M; the European Accessibility Act (June 2025) extends the obligation to e-commerce and digital services.
  • Measurable benefits: image indexing, rich snippets, a better mobile experience, less bouncing.
  • Tools: Lighthouse, axe, WAVE, and continuous tracking in your dashboard.

Web accessibility aims to make a site usable by everyone, including people with disabilities (sight, hearing, motor, cognitive) who use screen readers, keyboard navigation or display settings. In France, the framework is the RGAA (the general accessibility improvement framework). The connection with SEO is direct: Googlebot doesn't see the page, it reads it, like a screen reader. This article sets out the shared criteria, the legal obligations and the audit method.

Why accessibility and SEO overlap

Accessibility criterionEffect for the userSEO effect
Alt text on imagesThe screen reader describes the imageGoogle understands and indexes the image; see image indexing
A heading hierarchy (one H1, then H2, then H3)Navigation by headingA structure Google reads, better snippets, a table of contents in the results
Explicit links ("see the SEO programme" rather than "click here")Understandable out of contextDescriptive anchors, better relevance; see internal linking
Semantic HTML (nav, main, article, tables with headers)Landmarks for assistive technologyReliable content extraction, tables readable for snippets
Captions and transcripts for videoAccess for deaf peopleIndexable text content
Contrast and text sizeLegibilityLess bouncing, experience signals
Keyboard navigation, tab orderUsable without a mouseCrawlable forms and menus, no content trapped in JavaScript
A declared language (lang="fr")Correct pronunciationLanguage targeting
No content only as an image or in an untagged PDFAccess to the textIndexable content
Unique, descriptive page titlesIdentifying tabsThe title tag, the leading on-page factor
  • RGAA 4.1: the French transposition of WCAG 2.1 level AA, 106 criteria. Mandatory for public services, companies with revenue above €250 million and public-interest bodies, with a published accessibility statement and a multi-year plan. Penalty: up to €50,000 per non-compliant service, renewable.
  • The European Accessibility Act (directive 2019/882), applicable since 28 June 2025: extends the obligation to digital products and services sold to consumers: e-commerce, online banking, transport, telecoms, e-books, whatever the revenue, except micro-enterprises (fewer than 10 employees and €2M revenue). Existing sites have compliance deadlines, up to 2030 for some contracts.
  • Small business brochure sites: no direct obligation outside e-commerce, but a growing expectation from customers, tenders and public-sector buyers.

The accessibility statement, where mandatory, gives the compliance rate (criteria met / applicable criteria), the non-accessible content and a means of contact. A site counts as compliant from 100%, partially compliant from 50%.

The ten priority checks

  1. Every image carrying information has a descriptive alt attribute; decorative images have alt="".
  2. One H1 per page, with H2s and H3s in order and no skipped levels.
  3. Links have wording that is understandable out of context; identical links lead to the same target.
  4. Text/background contrast reaches 4.5:1 (3:1 for large text); checkable with Lighthouse or a contrast checker.
  5. Everything is usable by keyboard (Tab, Enter, Esc), with a visible focus; dropdown menus and modals close.
  6. Forms have labels (label) associated with each field, and explicit error messages.
  7. Videos have captions; podcasts have a transcript.
  8. The page has a unique title , a langattribute, and landmarks (header, nav, main, footer).
  9. Zooming to 200% doesn't break the layout; text isn't an image.
  10. Nothing flashes, and no media starts on its own with sound.

Auditing and tracking

ToolWhat it coversLimit
Lighthouse (Chrome, PageSpeed Insights)An accessibility score, contrast, alt, labels, ARIAAutomated: detects 30 to 40% of the criteria
axe DevTools, WAVEDetailed per-page analysis, errors and warningsPage by page
A crawler (Screaming Frog)Missing alt text, multiple headings, language, across the whole siteNo visual assessment
Manual testing with keyboard and screen reader (NVDA, VoiceOver)What the tools can't see: order, meaning, trapsTime
An RGAA audit by an expertThe 106 criteria, an official statement€1,500 to €6,000 depending on size
Continuous tracking in a dashboardA per-page score over time, regressions after updatesAutomated, to be completed by an annual manual test

Automated tools cover only part of the criteria; they are enough to fix the essentials (alt, contrast, structure, labels) and to watch for regressions. The RGAA statement requires a human audit. Accessibility fixes sit naturally within the full SEO audit and within work on Core Web Vitals, since they share the same templates.

Our advice: run Lighthouse on your three main templates (home, service page, article) and deal first with the contrast, alt and form label errors. They are the most frequent, the quickest to fix, and the ones that weigh most, for users and for Google alike.

How GreenRed helps

Rather than juggling several tools, GreenRed's web accessibility tracking brings these metrics together in a single dashboard, compares them over time and tells you which actions come first. You can try it free, with no card, from the Pricing.

Frequently asked questions

Does an accessible site rank better on Google?

Not directly: accessibility isn't a named ranking factor. But its criteria (alt text, heading structure, explicit links, semantic HTML, mobile legibility) are the ones that help Google understand the page, and they reduce bounce rate. An accessible site therefore stacks up the on-page SEO best practices.

Does my small business site have to comply with the RGAA?

The RGAA applies to public services and companies with revenue above €250M. Since June 2025, the European Accessibility Act has required accessibility of e-commerce and digital services sold to consumers, except micro-enterprises. A small business brochure site has no direct obligation, but public tenders and large accounts increasingly require it.

What is the difference between WCAG and RGAA?

The WCAG are the W3C's international standard (levels A, AA, AAA). The RGAA is the French method for verifying WCAG 2.1 level AA, with 106 criteria and precise tests. Being RGAA-compliant amounts to being WCAG AA-compliant, with an audit method recognised by the French administration.

How much does making a site accessible cost?

For a small business brochure site, the common fixes (alt, contrast, structure, forms, keyboard) come to 2 to 5 days of development, or €1,500 to €4,000. A full RGAA audit with a statement costs €1,500 to €6,000 depending on the number of pages and templates. Automated monthly tracking prevents regressions at each update.

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