Does an AI read pages in English for a question in French?
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Yes, and often. On our questions asked in French, 95% of ChatGPT's responses included at least one search in English, 75% for Gemini and 32% for Claude. Across about ten sectors queried in French, nearly half of the pages returned by the AIs were in English. And from one language to another, the sources almost all change: the domains cited for a question in French are found, for the same question in English, at only 1% for Claude, 14% for Gemini and 23% for ChatGPT.
For what type of question? It all depends on the question. On a subject that is highly documented in English, such as technology or health, AIs quickly go searching in English. On a subject specific to France, such as an administrative procedure or taxation, they stay more on French sources.
English searches for a French question
We read the searches that each AI writes before answering. On our questions asked in French on September 15, 2026, about 56% of ChatGPT's searches were in English, 42% for Gemini and 14% for Claude. 95% of ChatGPT's responses contained at least one. The subject of these questions, visibility in AI, is mainly documented in English, which drives these figures upward.
Across about ten sectors of activity queried in French, heritage, agriculture, health, historic buildings or professional software, nearly half of the pages returned by the three AIs were in English. The language of the question guides the search; it does not lock it in.
For a question in English, French pages disappear
The reverse is even more distinct. When we asked the same questions in English, Claude returned no French pages, in any sector, even for subjects specific to France such as inheritance tax. ChatGPT only cited French pages when it was an administration or a manufacturer named in the question. Gemini cited French pages in nearly half of the sectors.
For a client who queries an AI in English, a French company that only publishes in French is therefore almost invisible in Claude and ChatGPT, even when it is the best positioned on the subject.
From one language to another, almost no common sources left
We compared the domains cited for the same questions, asked first in French and then in English. In Claude, only 1% of the domains cited in French were also cited in English; in Gemini, 14%; in ChatGPT, 23%, mostly administrations and official sources. AIs do not translate their sources: they switch webs.
This also applies the other way around for citation rules. Some hold true in one language and not in the other: the freshness of a page, in one of our corpora, only played a role for pages in French; the question in the title or redundancy with other pages do not have the same effect in English as in French. A strategy thought out for French cannot be transposed as is.
What published studies say
We found no published study that measures the language of the sources cited by AIs according to the language of the question. Available studies, such as those by Ahrefs, Semrush, or Seer Interactive, almost all focus on queries in English and on the US market.
Google documents, on the other hand, that its AI features break down a question into multiple searches, and our measurements show that Gemini adds translations to its searches. Moving from one language to another is therefore part of the normal functioning of these tools, not an anomaly.
What this changes for a company
A French company that also targets clients abroad, or that works in a field documented in English, has an interest in publishing its important pages in both languages. An English version is not a courtesy translation: it is the only way to exist in the searches that AIs launch in English, including for French clients.
This is why the pages that FaireDuBruit distributes for its clients are published in French and in English. The effect of this double distribution on citations is not yet measured; what is measured is that without it, a large portion of searches cannot find the company.
What we do not know
The language of searches is detected automatically, with a portion of undecided searches: the percentages are orders of magnitude. The comparison between French and English is based on translated questions, asked to the same models, via their API. We do not measure the effect of a translation on citations.
Sources
- Google Search Central — "AI features and your website", .
- FaireDuBruit measurements, from September 4 to 16, 2026 — see "How we measured".