irsn.fr website review

75 files block the first paint until they finish downloading. Deferring or inlining them could save about 5.3 s.

About 455 KiB of CSS is downloaded but never applied on this page. Google estimates it would make the page about 2.3 s faster on a phone.

302 KiB could be saved by minifying CSS.

Your mobile performance score is 44. Under 50 is Google's “poor” band: many phone visitors leave before the page is usable.

4 images could be 458 KiB smaller with modern formats (WebP or AVIF) and sizes that fit a phone screen.

Web fonts hide text while they load. Setting font-display: swap shows text immediately (about 400 ms).

61 KiB could be saved by minifying JavaScript.

About 55 KiB of JavaScript is downloaded but never used on this page.

1 file is served with short cache lifetimes, so returning visitors download them again (22 KiB).

Critical files load one after another instead of in parallel (3 chains). Preconnecting to key origins and preloading the hero image shortens the chain.

Your largest element takes 8.7 s to render on a phone. Google's threshold for “good” is 2.5 s. The largest element is the image “Visuel site ASNR”.

The first text or image appears after 4.2 s on a phone. Good is under 1.8 s.

The layout shifts by 0.447 while loading, so content jumps under the reader's thumb. Good is under 0.1.

The page becomes fully interactive after 8.7 s. Good is under 3.8 s.

Over the last 25 four-week periods to 2026-10-31, real Chrome visitors' tap response (inp) went from 87 ms to 107 ms at the 75th percentile (Chrome UX Report (opens in a new tab) history).

Visually, the page fills in at 4.6 s (Speed Index). Good is under 3.4 s.

2 images have no width and height attributes, so the layout jumps as each one loads.

Over the last 25 four-week periods to 2026-10-31, real Chrome visitors' largest content (lcp) went from 2.0 s to 2.1 s at the 75th percentile (Chrome UX Report (opens in a new tab) history).

Your homepage downloads 2.5 MB in 112 requests on a phone: scripts 760 KiB (24), images 625 KiB (27) and fonts 577 KiB (5). Under 2 MB keeps phones on slow connections fast.

Visuel-bandeau-www-asnr-fr_250.jpg is on the first screen but marked loading="lazy", so the browser waits before fetching it and the page looks finished later. Load it eagerly (and give it fetchpriority="high" if it is the main image).

3 images (238 KiB) are JPEG, PNG or GIF. The same pictures as WebP or AVIF are usually much smaller at the same quality, and every current browser shows them.

By the Sustainable Web Design model, a visit to your homepage emits about 0.70 g of CO₂e: 83.6 kg a year at 10,000 visits a month. It scales with page weight, so every byte cut lowers it.

ARIA attributes must conform to valid values: 1 element on the page fails this check, rated critical by axe-core.

Links must have discernible text: 1 element on the page fails this check, rated serious by axe-core.

Contentinfo landmark should not be contained in another landmark: 1 element on the page fails this check, rated moderate by axe-core.

Document should not have more than one contentinfo landmark: 1 element on the page fails this check, rated moderate by axe-core.

Landmarks should have a unique role or role/label/title (i.e. accessible name) combination: 1 element on the page fails this check, rated moderate by axe-core.

All page content should be contained by landmarks: 1 element on the page fails this check, rated moderate by axe-core.

No structured data (JSON-LD), so Google can't show rich results such as your logo, ratings or FAQs.

No Open Graph image (also missing: og:title, og:description), so links shared on LinkedIn, Slack or Facebook show no preview picture.

The homepage links to 177 pages on irsn.fr and 25 external pages.

There is no Organization (or LocalBusiness) JSON-LD, so search engines and AI assistants have no machine-readable facts about who runs the site: its name, logo, profiles and contact details.

There is no https://recherche-expertise.asnr.fr/llms.txt, a short Markdown guide to your key pages for AI tools (llmstxt.org). It is optional and few AI tools read it yet, so treat it as a cheap extra.

https://recherche-expertise.asnr.fr/actualites/creation-lautorite-surete-nucleaire-radioprotection-asnr, https://recherche-expertise.asnr.fr/expertise, https://recherche-expertise.asnr.fr/expertise/avis-aux-autorites-par-annees, https://recherche-expertise.asnr.fr/avis-dexpertise-lasnr-2026, https://recherche-expertise.asnr.fr/avis-dexpertise-lasnr-2025 and https://recherche-expertise.asnr.fr/avis-lirsn-lannee-2024 and 9 others have no meta description, so Google writes the search snippet from whatever text it finds.

We fetched 15 pages linked from your homepage (of 146 found) and read each the way a search engine does.

1 error was logged to the browser console while the page loaded, for example “The Content Security Policy directive 'upgrade-insecure-requests' is ignored when delivered in a report-only policy.”.

1 image is served at too low a resolution for sharp phone screens.

Large scripts ship without source maps.

On a phone, there is no call to action on the first screen: visitors have to scroll to find out what to do next.

We found no call-to-action buttons or links (such as “Book a demo” or “Get a quote”) anywhere on the homepage.

No testimonials, customer logos, ratings or customer counts on the homepage: nothing tells a new visitor that others already trust you.

No phone number or email link on the homepage, so ready-to-buy visitors have one fewer way to reach you.

No guarantee or risk reducer (money-back, free trial, no credit card) is mentioned, which is often what tips a hesitant visitor.

The homepage carries about 804 words of visible text.

Opening the homepage sets 3 cookies (measured from a US location before any click).

No known cookie consent tool loads with the page. Some sites build their own banner, and some only show one to visitors from the EU.