Firefox's AI Smart Window adds Mistral and expands to France

Mozilla and French AI company Mistral announced a partnership on September 16, 2026, that brings Mistral’s models to Smart Window, Firefox’s AI browsing assistant. Mistral Small 4 is now one of the models Smart Window users in the US and Canada can pick, and the Smart Window beta is expanding to France with French-language support. The UK and Germany are due to follow later this year.

What Mozilla and Mistral announced

• A new model: Mistral Small 4 joins Smart Window as a model choice for users in the US and Canada.
• A new country: France is Smart Window’s first market outside North America, with official French-language support.
• More to come: Mistral says it will help power Smart Window in the United Kingdom and Germany later in 2026, with models tuned for regional languages and cultural context.
• Privacy terms: according to Mistral, conversations aren’t saved on Mozilla’s servers by default, and partners such as Mistral agree to zero data retention.

Both companies present the deal as a vote for open models and competition. Mozilla’s chief executive, Anthony Enzor-DeMeo, said a browser “shouldn’t be a one-way funnel”, while Mistral’s co-founder and chief executive, Arthur Mensch, described it as two open-source advocates working together.

What is Firefox Smart Window?

Mozilla introduced Smart Window in August 2026 as a privacy-first, AI-powered way to browse, designed to help people finish what they start online. It works with the browsing context you choose to share, such as open tabs and relevant history, and it can:

• Answer questions from the current web, showing its sources, without sending you to a page of search results.
• Tidy your tabs, suggesting groups for related tabs and spotting duplicates.
• Help you find pages again, with visual previews of sites in your history.

Smart Window is optional and still in beta. Mozilla says you choose when to use it, what browsing context it can see and which AI model answers.

Three models to choose from

When you first open Smart Window, you pick the model behind its assistant. Mozilla labels each one by what it’s good at:

More advanced users can connect their own model instead. You can change your default model in Settings, then AI controls, then Smart Window settings, or switch models for a single chat from the model selector in the chat window. Each user gets a generous daily usage quota, which resets the next day.

Who can get Smart Window

Smart Window is rolling out gradually:

• US and Canada: in English, starting with Firefox 150.
• France: in French, starting with Firefox 155.
• UK and Germany: expected later in 2026.

If you live somewhere else, Mozilla lets you sign up to be told when Smart Window reaches your country.

How to turn off AI features in Firefox

Firefox makes every generative AI feature optional. On desktop, Firefox 148 and later include an AI Controls panel:

1. Click the menu button and select Settings.
2. Select AI Controls on the left.
3. Turn on Block AI enhancements to hide all current and future AI features, including prompts to try them.

To keep some features, leave the switch on and set individual features to Available or Enabled, or switch it off and set only the features you don’t want — Smart Window, the AI chatbot in the sidebar, AI-enhanced tab groups, link preview key points and more — to Blocked. Blocking an on-device feature also removes any AI models Firefox has already downloaded for it. Extensions can still use outside AI services on their own.

Why it matters

Chrome and Microsoft Edge each build in their own company’s assistant — Gemini and Copilot. Firefox is taking the opposite approach, letting you pick from several models, including one from European company Mistral, or turn AI off entirely. If you use another browser’s assistant and want it gone, we explain how to turn off Gemini in Chrome and how to turn off Copilot in Edge. For a side-by-side look at every option, see our guide to the best AI browsers.