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I want to translate a sentence that says something like “By the way, did you remember to get…?”

So far I've seen two options: au fait and à propos. Which one would be more appropriate for an informal talk?

J'aimerais traduire une phrase du type « By the way, did you remember to get…? », pour l'instant je vois deux possibilités, « au fait » et « à propos ». Laquelle est la plus adaptée dans le cadre d'une discussion informelle ?

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D'ailleurs would be another possibility, it is roughly equivalent to à propos. – Evpok Aug 26 '11 at 11:23
"a propos" is not a french therm. is international one see – serhio Aug 27 '11 at 16:37
As far as using them in a text, they are interchangeable. – Sifu Aug 8 '14 at 15:23

10 Answers 10

up vote 38 down vote accepted

Both are correct.

  • Au fait : what you are going to say relates to what you've been talking about.
  • À propos : might indicate a switch to another subject.
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Je ne sais pas si c'est un québécisme ou du vernaculaire, mais j'entends souvent "en passant" aussi. – asmo Aug 26 '11 at 16:18
Je ne suis pas d'accord. Pour moi, les deux sont faux, voir ma réponse. – Kheldar Aug 26 '11 at 17:32

« Au passage, … » qui ressemble assez fortement à la version anglaise fonctionne plutôt bien à l'oral, et même parfois à l'écrit. En français, le sens littéral est plus souvent respecté qu'en anglais. Dans les cas où le « chemin » n'est pas suffisament matérialisé, plusieurs variantes existent :

  • Au fait, (introduction d'un nouvel élément factuel lié au sujet)
  • D'ailleurs, (introduction d'un sujet lié mais distinct)
  • À propos, (introduction d'un sujet qui peut avoir une influence sur la discussion précédente)
  • Tant qu'on y est, (quitte à parler de ça, autant pousser la discussion jusque là / jusqu'au bout…)
  • Puisque tu le dis, Maintenant que tu le dis, (oral)(introduction d'un fait ou d'une idée en tenant compte du propos de l'interlocuteur).
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Maybe also "Si jamais"? – Benjol Aug 12 '14 at 8:05

In Canadian French, we use en passant.

En passant, t'es tu rappelé de prendre…

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In maybe a more familiar way, there's also :

  • "Au passage"
  • "Tant qu'on y est" depending on the context. I think it refers mostly to actions like "Tant qu'on y est, on devrait laver la cuisine." / "By the way, we should wash the kitchen" but I'm not quite sure of this one.
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Two variants (although not well suited to the original example): en passant and tant que j'y pense – Joubarc Aug 26 '11 at 12:01

There's also tiens, which can precede about every answer mentionned yet:

Tiens, au fait, tu as pensé à acheter des galets ?

Tiens, à propos, as-tu pensé à acheter des galets ? (By the way, it's grammatically better to say as-tu than tu as for a question, but that's another question)

Tiens, en passant, as-tu pensé à acheter des galets ?

But it's also worth noting that it's also used on its own:

Tiens, tu y as pensé, cette fois ?

Although it's quite informal (and somehow implies that's you're on a first-name basis) and I have no real clue why it's used that way (worth yet another question) as you're not actually asking the person to hold anything.

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To add to the translations proposed by @zejam

  • Au fait
  • À propos (à ce propos)

I think some sentences could be translate with

  • D'ailleurs
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I'm Belgian (Dutch part), and we have many dialects.

I'm from the the most westerly part, where the dialect uses a lot of French words. We often use "à propos" to indicate what you are trying to achieve.

So even outside of French, "à propos" is used to say "by the way".

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Yes, basically they are interchangable, it will depend only of your level of language :

  • Au fait - Everyday language, casual register
  • D'ailleurs - Everyday language too, less casual
  • A propos - Used also in everyday language too but less casual thant the two others
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I'd say à propos is slightly more formal than the other two. But all in all, there are totally interchangeable.

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  • Au fait, means: let's get to the bottom of this. It is usually used as "by the way" but should not.

  • À propos, means: This subject is related to this new idea I'm going to talk about.

I would use "Au passage" or "Pendant qu'on y est".

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Au fait actually abbreviates: "allons droit au fait". – Kheldar Aug 26 '11 at 17:31
If it is used as by the way, then it means by the way. – Evpok Aug 26 '11 at 21:06
Au fait can mean several things (see e.g. section C of the TLF article for fait), but the meaning in this context is not “let's get to the bottom of this” (sense C.1, which is arelatively rare one), it's “by the way” (sense C.4). À propos does mean what you say it means, and by the way can mean this too. – Gilles Aug 26 '11 at 23:50
@Kheldar Even the highly prescriptive Académie mentions this meaning of au fait. I don't see on what basis you can consider it wrong. – Gilles Aug 27 '11 at 8:50
Historically, it is true. And indeed, sometime, one can say « Au fait ! », with an imperative tone, to say to go to the core. But in current spoken French, « au fait » is used in a somewhat opposite sense, in a sense of « ça me fait penser à... », to a perhaps unrelated topic. Same for « à propos », which is often used to err from the topic... Yes, sometime, French people aren't so Cartesian/logical... Actually, if we really want to remain on topic, we rather use « À ce propos », putting more emphasis on the topic. – PhiLho Sep 6 '11 at 12:49

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