Take these two constructions:

Il ne faut pas partir


On ne doit pas partir

Am I right that these both mean "It's not necessary to leave"?

And then this:

Il faut ne pas partir


On doit ne pas partir

Am I right that these both mean "It's necessary not to leave"?

Lastly, is it normal to leave out the ne in a negative infinitive in casual speech, just as in other conjugations, i.e. On doit pas partir ?

  • This might be of interest if you have not read it already. french.stackexchange.com/questions/2234/… Commented Apr 22, 2016 at 16:54
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    Concerning your “lastly”. Oui, mais il faut pas le faire. Commented Apr 22, 2016 at 16:56
  • Wait....Do you mean il ne faut pas le faire or il faut ne pas le faire.....surely there's a way to differentiate this with where you place the stress when speaking aloud? Commented Apr 22, 2016 at 17:31
  • Right. I mean (or rather I don't…) “il ne faut pas le faire”. “Il faut ne pas faire quelque chose” is not the normal way to phrase it. But it could occur in sentences like “Pour se sentir mieux, il faut ne pas y penser” (hard to explain why). Commented Apr 22, 2016 at 19:02
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    @ladit: je ne le peux que constater ;-) Commented Apr 23, 2016 at 21:45

2 Answers 2


Native French speaker here. I can understand why you're confused: when I learned English, I was surprised at how clear the distinctions were... and still they were hard for me to remember.

"Il ne faut pas partir" means that you MUST NOT leave, as in you have to stay where you are, by default. In specific contexts, it could mean that you DON'T HAVE TO leave, but in this case, emphasis will be put on "faut", as in, "it's not that we HAVE TO leave... [but I think we should get going anyway]"

"On ne doit pas partir" is similar, but maybe slightly more ambiguous. Out of context, it means that you MUST NOT leave, by default, and then in specific contexts and/or if you put the emphasis on "doit", it can mean that you DON'T HAVE TO leave.

"Il faut ne pas partir" and "On doit ne pas partir" sound very unnatural to me. The syntax does exist, but it's very rarely used, so rarely in fact that I can't think of a proper example. In both cases, it would mean "we must [not leave]" so "we must stay".

To express the idea that you DON'T HAVE TO leave, without ambiguity, I would recommend the following : "On n'est pas obligé(s) de partir." (without the S for impersonal "on", with it if it really means "we", and if it means "we" and refers to an all-female group, the ending is "ées"). In everyday conversation, you might also come across "On n'a pas besoin de partir", or "I don't need to leave": normally it refers to literal needs, but it is sometimes used in spoken language to mean the absence of obligation just like "don't need to" can mean "don't have to" in English.

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    That is so stupid! Il ne faut pas partir having the meaning of "you must not leave* just doesn't make sense, that's simply not what it says in a literal sense....it says "It's not necessary to leave.* I understand, I just resent the lack of logic in the meaning. Commented Apr 24, 2016 at 5:10
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    @Aerovistae Yes, I can understand your frustration. I wonder, does it mean that deep inside we believe that not having to do something is almost the same as having to do the opposite? I suppose this question would take a philosophy thesis to answer but... It's interesting ^^
    – Pwassonne
    Commented Apr 24, 2016 at 20:03
  • Il ne faut pas partir [trop tôt ou maintenant ou demain], pourquoi pas?
    – Lambie
    Commented Sep 3, 2019 at 18:06

You're both wrong and right actually, the first two exemples are less restrictive, it's more like "we shouldn't leave"

The second two exemple are more restrictives and like "we can't leave"

But there isn't "nécessairement" in both exemples so you shouldn't translate it in your sentence, it's more in the meaning that "necesserary" is present than in the sentence.

  • Welcome to Stack Exchange, lili! Your answer here was a little unclear, so I think that's why someone downvoted you. Sometimes people don't explain their downvotes :( At any rate, it would be helpful if you would elaborate on what you mean here. And yes, I know the word nécessaire is not literally present in the sentence....it was just one way of translating it, which I used because it made very clear the distinction I was trying to make between meanings. With necessary, the meaning is approximately the same in English, though indeed the English phrasing is less than perfectly natural. Commented Apr 24, 2016 at 5:13

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