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 ?

  • 9
    D'ailleurs would be another possibility, it is roughly equivalent to à propos.
    – Evpok
    Commented Aug 26, 2011 at 11:23
  • "a propos" is not a french therm. is international one see en.wiktionary.org/wiki/apropos
    – serhio
    Commented Aug 27, 2011 at 16:37
  • As far as using them in a text, they are interchangeable.
    – Sifu
    Commented Aug 8, 2014 at 15:23

12 Answers 12


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.
  • 6
    Je ne sais pas si c'est un québécisme ou du vernaculaire, mais j'entends souvent "en passant" aussi.
    – user259
    Commented Aug 26, 2011 at 16:18
  • Je ne suis pas d'accord. Pour moi, les deux sont faux, voir ma réponse.
    – Kheldar
    Commented Aug 26, 2011 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).
  • Maybe also "Si jamais"?
    – Benjol
    Commented Aug 12, 2014 at 8:05

In Canadian French, we use en passant.

En passant, t'es tu rappelé de prendre…

  • Never heard that in my life, probably because I'm Parisian
    – JKHA
    Commented May 21, 2019 at 14:40

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.
  • 3
    Two variants (although not well suited to the original example): en passant and tant que j'y pense
    – Joubarc
    Commented Aug 26, 2011 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.


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

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".


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

I'd say à propos is slightly more formal than the other two. But all in all, there are totally interchangeable.


I see there is the Canadian French "En passant" among the answers.

In France, "En passant" is not common, one would rather say "Soit dit en passant".

  • Qu'il me soit permis de remarquer, en passant, que cette proposition peut être inversée (Baudelaire). Cette affirmation n'est pas étayée, pas plus que celle qui dit que c'est du français du Canada, puisqu'on retrouve cet exemple au TLFi et que Ac.9 contient aussi la locution...
    – user19187
    Commented May 20, 2019 at 0:38
  • @Survenant9r7 1/ "Not common" ne signifie pas que ça n'existe pas, mais qu'on ne l'entend pas souvent. Vous avez un exemple plus récent que Baudelaire ? 2/ Je parlais de l'emploi d'en passant "tout seul" (cf la réponse qui parle de Canadien Français) : "soit dit en passant" est fréquent, et, je n'y avais pas pensé, "vous remarquerez en passant" aussi. Mais je ne l'ai encore jamais vu tout seul, dans ce sens-là.
    – user20728
    Commented May 20, 2019 at 5:46
  • Difficile à dénicher en effet, j'ai essayé avec "En passant" site:lexpress.fr -"en passant par", le temps me manque, je l'ai trouvé dans une traduction des propos de Trump ici, sinon oui avec remarquer, rappeler, mentionner. Oui je faisais référence à l'affirmation de l'autre réponse, c'est un peu injuste pour la tienne, quand je parlais du français du Canada. On pourrait probablement étayer que ce n'est pas courant en effet. Vu ça, +1.
    – user19187
    Commented May 20, 2019 at 7:16

By the way in English always introduces what is called an afterthought: Here's an example.

"We spent three weeks in the mountains camping, you know. It was so much fun. We hiked every day farther up the trails and also just hung out a lot. By the way, have you spoken to John recently?"

By the way is a subject shifter. The speaker is shifting to another idea that is completely unrelated to the previous subject he or she has been talking about.

Au fait and à propos can both be used like this. D'ailleurs cannot. It means besides.

Wikipedia: locution conjonctive: Se dit lorsqu’on vient à parler de quelque chose dont on se souvient subitement : introduit un changement de sujet, une idée secondaire ou une parenthèse dans un cheminement logique.

  • 3
    "By the way" can be used like you're saying, but it is also often used to introduce something that is, yes, different from the previous subject, but also related. A synonym could be "incidentally". It is not always passer du coq à l'âne. To take your example, saying "By the way, the flashlight you loaned me came in very handy." would be natural. I don't think the answer to this question is as cut and dry as you make it sound. Definitely depends on context.
    – Kareen
    Commented Oct 30, 2016 at 18:14
  • @Kareen The phrase "by the way" can be used as you said. (not like) "By the way, the flashlight you lent me came in very handy." (lend is preferable to loan as a verb in good writing) "incidentally" and "by the way" are the same thing. Both are subject shifters. By the way, I would never say "loan someone a flashlight", which is most definitely not my example. I believe this is cut-and- dried usage. Anything else?
    – Lambie
    Commented Jul 24, 2019 at 14:28
  • You also might want to comment on the answer with 52 points, which doesn't even have any references.
    – Lambie
    Commented Jul 24, 2019 at 14:34


  • 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".

  • 2
    Au fait actually abbreviates: "allons droit au fait".
    – Kheldar
    Commented Aug 26, 2011 at 17:31
  • 6
    If it is used as by the way, then it means by the way.
    – Evpok
    Commented Aug 26, 2011 at 21:06
  • 1
    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. Commented Aug 26, 2011 at 23:50
  • 6
    @Kheldar Even the highly prescriptive Académie mentions this meaning of au fait. I don't see on what basis you can consider it wrong. Commented Aug 27, 2011 at 8:50
  • 2
    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
    Commented Sep 6, 2011 at 12:49

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