French Grammar Checker: The 5 Best Tools Compared

Most of my adult students already use a French grammar checker. The problem is how they use it: they paste a paragraph, click "accept" on every suggestion, and send it. The text comes back cleaner, but they make the same five mistakes next week, because nobody told them why.

A good French grammar checker is a mirror, not a crutch. This page compares the five tools worth your time (LanguageTool, Antidote, BonPatron, Scribens and Grammalecte), shows you a real test on nine classic English-speaker mistakes, and gives you a simple routine so the checker teaches you something every time you use it.

The best French grammar checker at a glance

Here is the short version, as of October 2026, based on each tool's official site and my own test.

My recommendation: start with LanguageTool, add Antidote if French becomes part of your job or studies, and use BonPatron as a second opinion when you're not sure why something is wrong.

Tip from class: never use two checkers at the same time on the same text. You'll get conflicting suggestions and accept the wrong one. Fix with one, then double-check with the other.

How I tested a French grammar checker

I wrote six short sentences containing nine mistakes I correct in lessons every week, then ran the text through LanguageTool's free public checker on October 20, 2026. Here is the text, exactly as I submitted it:

Hier, je suis aller au marché avec mes amis. Nous avons acheter des pommes rouge et une baguette. La femme qui vend les fromage était très gentille. Je veux que tu viens avec moi samedi. Mes parents sont arrivé a Montréal la semaine dernier. Il est un professeur.

And here is what LanguageTool flagged:

Seven out of nine is a strong result for a free tool. It caught the two mistakes I see most from English speakers (infinitive instead of past participle, and the missing subjunctive after je veux que) and explained each one.

The two misses are telling. Dernier has to agree with semaine, a feminine noun, but the checker didn't connect them. And Il est un professeur is grammatically possible in rare contexts, so a cautious checker lets it pass, even though a French speaker would say C'est un professeur (He's a teacher) or Il est professeur, with no article.

I also tried to run the same text through Reverso and BonPatron automatically, but their sites blocked the test, so I'm not giving them a score. Copy the text above into any checker you're considering and compare it with my answer key. It takes two minutes and tells you more than any review.

LanguageTool: the best free French grammar checker

LanguageTool corrects French spelling, grammar, punctuation, capitalization and style, and suggests rewordings and synonyms. It covers more than 30 languages and dialects, which is handy if you also write in English or Spanish. Its core is open source, with the code published on GitHub.

What makes it the best default for learners is where it lives: there are extensions for Chrome, Firefox, Edge, Opera and Safari, add-ins for Google Docs, Word, Apple Pages and LibreOffice, and support for Gmail, Outlook, Apple Mail and Thunderbird. You check your French where you write it, without copy-pasting.

The free version covers spelling, style and punctuation errors; LanguageTool's own site says Premium "corrects all errors." In my test the free version still caught grammar mistakes such as agreement and the subjunctive, so start free and upgrade only if you write long texts often.

Antidote: the most complete option

Antidote, made by Druide informatique, is three tools in one: a corrector, a set of dictionaries (definitions, synonyms, antonyms) and a library of 578 guide articles on grammar, style, spelling and punctuation. The current version is Antidote 12, and the Antidote+ and Antidote Pro subscriptions add an AI rewording mode (rewrite, soften, shorten).

The real advantage for a learner is the guides. When Antidote flags an agreement, you can open the rule behind it in one click. That turns every correction into a mini-lesson.

Antidote runs on Windows and Mac, on the web and on mobile, and plugs into Word and web browsers. It's sold by subscription, with separate plans for organizations. Choose it if you're studying in French, preparing for a French-speaking workplace, or writing every day.

BonPatron: made for learners of French

BonPatron is an online checker built specifically for French as a second language, by Nadaclair Language Technologies. Its site says it was "built by teachers," and you can tell: there's a setting to say that je is feminine, so it checks je suis allée correctly, and another to say whether you're a native speaker.

That first option matters more than it sounds. A checker can't know who je is, so without that setting it has no reason to flag a woman writing je suis allé. If you're a woman learning French, turn that setting on and keep it on.

BonPatron is free in your browser, with a paid Pro version. It doesn't plug into your other apps, so use it for important texts: a cover letter, an email to a landlord in Québec, a DELF writing task.

Scribens and Grammalecte: two free second opinions

Scribens is a free online checker that covers more than 40 languages, French included. It checks conjugation, agreement, homophones, punctuation and typography, and explains its corrections. The free plan is limited to 8,000 characters a day, while Premium allows up to 5 million characters a month and 100,000 per check, plus a paraphrasing tool. It also has add-ons for Word, Google Docs, Gmail, Chrome and Firefox.

Grammalecte is a free, open-source (GPL 3) French grammar and typography checker that runs in LibreOffice, Firefox and Thunderbird, with limited Chrome support. Its philosophy is the opposite of most tools: it aims for as few false alarms as possible, so if it isn't fairly sure a phrase is wrong, it says nothing. That makes it quieter than LanguageTool, but when it does flag something, take it seriously.

How to use a French grammar checker without becoming dependent

This is the routine I give my students. It takes five extra minutes and it's where the learning happens.

1. Write first, check later. Finish your paragraph without the checker running. If the underlines appear while you type, you stop thinking about the French.
2. Reread it aloud once. You'll catch some mistakes yourself, especially missing words.
3. Run the checker, then pause on each suggestion. Before you accept, say why it's wrong: "agreement with parents, masculine plural."
4. Keep a mistake log. Write down every error you make twice. Most learners have five or six repeat mistakes, not fifty.
5. Ignore suggestions you can't explain. Ask your teacher instead. Accepting blindly is how wrong corrections creep in.

If your mistakes are mostly agreements, our guide to French adjective agreement and placement will fix most of them. If the checker keeps flagging your past tenses, read passé composé vs imparfait next.

Common mistakes English speakers make with grammar checkers

• Mistake: Accepting every suggestion → Do instead: Accept only what you can explain, and log the rest.
• Mistake: Typing without accents and letting the checker add them → Do instead: Learn the shortcuts once with our French accents keyboard guide. When both spellings are real words, like ou (or) and où (where), a checker can only guess from context.
• Mistake: Checking English-style sentences translated word for word → Do instead: Write simpler French. A checker can fix aller to allé, but it can't fix a sentence built on English logic.
• Mistake: Thinking "no underline" means "correct" → Do instead: Remember the misses in my test. Our list of common French mistakes English speakers make covers the ones checkers rarely flag.
• Mistake: Forgetting your gender setting → Do instead: If you're a woman, set it in BonPatron, and check je suis allée, je suis contente yourself in other tools.

Practice

Find and fix the mistake in each sentence before you run any checker. Answers below.

1. Elle est allé au cinéma.
2. Nous avons manger une pizza.
3. Il faut que tu fais tes devoirs.
4. J'habite a Toronto.
5. Mes sœurs sont très gentil.

Answers: 1. Elle est allée au cinéma. · 2. Nous avons mangé une pizza. · 3. Il faut que tu fasses tes devoirs (subjunctive, see our French subjunctive guide). · 4. J'habite à Toronto. · 5. Mes sœurs sont très gentilles.

In short

The best French grammar checker for most learners is LanguageTool: free, available wherever you write, and in my test it caught seven of nine classic mistakes. Upgrade to Antidote if you write French every day, and use BonPatron when you want feedback designed for learners. Whatever you choose, use it after you write, not while you write, and turn every correction into a rule you understand.

A checker tells you what's wrong; a teacher tells you why you keep doing it. If you'd like Magali to look at your writing and find the three mistakes that cost you the most, book a free 30-minute assessment. You'll leave with a short personal list to watch for, before any checker has to.