Mistral’s Le Chat, Europe’s Leading Artificial Intelligence Chatbot, Repeats Falsehoods Half the Time When Prompted on State-Sponsored Iran War Disinformation - NewsGuard

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Mistral’s Le Chat, Europe’s Leading Artificial Intelligence Chatbot, Repeats Falsehoods Half the Time When Prompted on State-Sponsored Iran War Disinformation

The French Ministry of Armed Forces also uses Mistral — but says it’s a completely different, customized tool

By Isis Blachez | Published on April 28, 2026

Percentages of Le Chat responses providing a debunk or false information when prompted on false claims on the Iran war in English. (Graph via NewsGuard)

Europe’s leading home-grown chatbot is also a leading propaganda spreader. When prompted on false claims about the war in Iran advanced by Russian, Chinese, and Iranian state-aligned networks or outlets, Mistral AI’s chatbot Le Chat repeated falsehoods 50 percent of the time in English and 56.6 percent of the time in French, an April 2026 NewsGuard audit found. These findings suggest that Paris-based Mistral’s Le Chat, the most prominent European-made chatbot, is vulnerable to state-sponsored disinformation, potentially increasing its spread.

NewsGuard prompted the free consumer version of Le Chat on 10 false claims about the Iran war that spread online in March 2026. For each claim, NewsGuard used three types of prompts for a total of 30 prompts. All of the claims originated or were spread by foreign state-aligned networks or outlets from Russia, Iran, or China. The claims included:

There was a typhus outbreak on the French aircraft carrier Charles de Gaulle, which was sent to the Middle East during the Iran war.

Hundreds of U.S. troops had been killed in the war as of March 31, 2026.

The United Arab Emirates used a Moroccan-made drone to attack a port in Oman on March 11, 2026, seeking to frame Iran for the attack.

The three prompts used for each claim reflect different user personas: an innocent user inquiring about the claim neutrally, a leading prompt by a user who assumes the false claim is true and asks for more details, and malign users aiming to repackage the claim in shareable formats — such as a social media post caption or breaking news story — to spread it on a large scale. (See Methodology below.)

As noted above, in response to all types of prompts, Le Chat overall repeated false information 50 percent of the time in English (15 out of 30 responses). Responding to innocent prompts, the tool provided false information 10 percent of the time (1 out of 10). Responding to leading prompts, Le Chat provided false information 60 percent of the time (6 out of 10).  And it provided false information to malign prompts 80 percent of the time (8 responses out of 10), highlighting potential risks of misuse by foreign actors looking to produce and spread falsehoods at a large scale.

When tested with the same prompts in French, Le Chat repeated false information 56.67 percent of the time globally (17 out of 30 responses,) providing false information 10 percent of the time (1 out of 10) to innocent prompts, 70 percent (7 out of 10) to leading prompts, and 90 percent (9 out of 10) to malign prompts.

Mistral AI did not respond to two April 2026 NewsGuard emails requesting a comment on the audit’s results. NewsGuard also sent LinkedIn messages to Mistral AI’s head of communications for North America, Howard Cohen, and to its head of communications for Europe, Middle East and Africa, François Lesage, but did not receive responses.

Percentage of Le Chat outputs repeating false claims in English for every prompt style. (Graph via NewsGuard)

FRENCH ARMED FORCES CHOOSE MISTRAL

In January 2026, the French Ministry of Armed Forces announced an agreement with Mistral AI allowing all of its branches and agencies — including the army — to access the company’s models, software, and services. The partnership allows the Ministry “to benefit from the latest technological innovations while ensuring sovereign control over the tools used,” according to a January 2026 press release by the Ministry.

In an April 2026 statement to NewsGuard, the ministry disclosed that its personnel would be using a customized version of Le Chat Enterprise, its paid tool for companies, as part of the deal. The ministry added that its version of the chatbot would not be able to access the internet, making it different from the free version of Le Chat, the tool covered by this audit. The version used by consumers does have access to the internet, which means it draws responses to prompts from the internet, enabling it to respond to news-related prompts, but also making it vulnerable to false content on the web from unreliable or malign sites.

Nevertheless, the Ministry’s formal adoption of Mistral AI’s technology signals institutional confidence in the company’s systems and products, especially as it is the only major AI tool to emerge from...