Conjonctions Conditionnelles (autres que si)

French speakers have far more than si (if) to express conditions. They have a whole vocabulary for nuancing the kind of condition: provided that, unless, in case, supposing that, insofar as, on the condition that. Each of these expressions carves out a slightly different shade of conditional logic — and each comes with its own mood requirement, often the subjunctive, sometimes the conditional, occasionally the indicative. The mood tells you something real about the condition: subjunctive for hypothetical or unconfirmed events, conditional for hypothetical futures, indicative for facts being framed as conditions.

The single most surprising fact for English speakers is that au cas où (in case) takes the conditional, not the subjunctive. It is the only common French conjunction with this property, and it is entirely opaque from English. Learners who have memorized bien que + subjunctive and à condition que + subjunctive will reach for the same trigger logic with au cas où and produce the wrong form. This page sorts out the family piece by piece.

à condition que — provided that (subjunctive)

À condition que is the most precise of the if-and-only-if conjunctions. It introduces a necessary condition for the main clause to hold: I'll do X provided that you do Y. It always takes the subjunctive.

The condition expressed by à condition que feels stronger than si. Si tu viens, je serai content (if you come, I'll be happy) is open and casual. À condition que tu viennes, je serai content (provided you come, I'll be happy) implies a stipulation, almost a contract. Native speakers reach for à condition que in negotiations, in formal proposals, and in conversations where they want to make their condition explicit.

Same-subject reduction: à condition de + infinitive

When the subjects of the two clauses match, French collapses to à condition de + infinitive — never à condition que + subjunctive.

This same-subject reduction is mandatory in careful French. Use the que + subjunctive form only when the subjects differ.

à moins que — unless (subjunctive + ne explétif)

À moins que is the negation of si — it introduces the escape clause: X will happen, unless Y intervenes. It takes the subjunctive, and traditionally also the ne explétif — a non-negating ne that appears for stylistic reasons.

The ne in these sentences is not negating. It does not turn unless it rains into unless it doesn't rain. It is a stylistic marker that flags the formal register and the à moins que construction itself. In conversation it is widely dropped; in writing it is more common.

The à moins que construction is also reducible to à moins de + infinitive when subjects match:

pourvu que — provided that, as long as (subjunctive)

Pourvu que is a close cousin of à condition que, but it carries a slightly different feel: it is more permissive, more as long as than strictly provided that. It takes the subjunctive.

Pourvu que has a second, very common life: as a stand-alone wish at the start of a sentence, with no main clause attached. In this use it means let's hope that / if only.

This is one of the most natural ways to express hope in French — much more frequent than the textbook j'espère que in spoken speech. Notice the lack of an exclamation mark in some uses; either is fine, but the spoken form often carries strong intonation.

en cas de + noun — in case of

En cas de is the prepositional member of the family. It takes a noun phrase, not a clause, and is widely used on signs, in instructions, and in any anticipatory or precautionary context.

To convert a clause to en cas de, you nominalize: en cas de pluie (in case of rain), not *en cas qu'il pleuve. The noun version is the only form available — there is no *en cas que.

au cas où + conditional — in case (THE EXCEPTION)

This is the conjunction that breaks the pattern. Au cas où introduces a hypothetical event that you are preparing for, and unlike every other common conditional conjunction, it takes the conditional mood, not the subjunctive.

The conditional makes sense once you see what au cas où is actually doing: it is describing a hypothetical would-happen event. Au cas où il pleuvrait literally means in the case that it would rain — a hypothetical condition projected into a possible future. The conditional mood is exactly the form for hypotheticals projected from the present, and French uses it consistently here.

For a hypothetical past, au cas où takes the conditional past:

In English, in case triggers the present (in case it rains) or the past (in case he forgot). French is more explicit about the hypothetical nature of the event by using the conditional.

supposons que / admettons que — supposing that, let's say (subjunctive)

These two are imperative-form conjunctions used to introduce a hypothesis for the sake of argument. Both take the subjunctive.

These are most at home in arguments, problem-solving, and hypothetical reasoning. Admettons que in particular has a debate-room feel — let's grant your point and see where it leads. The related à supposer que is more formal and also takes the subjunctive:

dans la mesure où + indicative — insofar as

Dans la mesure où (insofar as, to the extent that) is the only conjunction in this group that takes the indicative. The reason: it is not really a hypothetical condition; it is a factual qualification. Insofar as X is true, Y follows. The clause is being asserted as a true measure, not as a hypothetical.

This is a high-register, slightly bureaucratic conjunction, common in formal writing, news, and academic prose. In conversation it sounds careful and deliberate. The indicative is the giveaway: this is a fact-based qualification, not a pure hypothetical.

pour peu que — provided that, if even (subjunctive)

Pour peu que introduces a minimal sufficient condition — as long as the slightest amount of X. It takes the subjunctive and is somewhat formal.

The flavor is if even a little, the slightest trigger and. This conjunction is more common in writing and considered prose than in casual conversation, but it is recognizable to all educated speakers.

quand bien même + conditional — even if (literary)

Quand bien même (even if, even though) is a literary counterpart to même si, but with a striking grammatical difference: it takes the conditional in both clauses, not the indicative.

This is high-register French, found in essays, formal speech, and literature. Conversational French uses même si + indicative for the same idea. Recognize quand bien même in reading; default to même si in your own production.

Mood selection: a summary

The key generalization: when the conjunction projects a hypothetical event whose realization is unconfirmed, French uses the subjunctive by default. When the conjunction frames a hypothetical would-happen event from a present perspective (in the eventuality that), French uses the conditional. When the conjunction asserts a factual measure or extent, French uses the indicative.

Common Mistakes

This is the most-stigmatized error in this family. Learners apply the bien que / pour que / à condition que / subjunctive rule to au cas où and produce the wrong form. Au cas où is the exception: conditional only.

In careful writing, à moins que normally carries the ne explétif. In casual speech, it is often dropped. Know that the ne is not a negation — it is a stylistic feature.

There is no en cas que. To use a clause, switch to au cas où + conditional. To stay with en cas de, you must nominalize.

When subjects match, use à condition de + infinitive. When they differ, use à condition que + finite subjunctive. The infinitive cannot follow que.

Dans la mesure où is a fact-based qualification. Subjunctive is wrong here; indicative is required.

Key takeaways

The non-si conditional family expresses fine-grained shades of conditionality that English handles through periphrastic constructions: provided that, unless, as long as, insofar as, in case. Most of these conjunctions trigger the subjunctive, but two break the pattern in important ways: au cas où and quand bien même take the conditional, and dans la mesure où takes the indicative. The subjunctive marks pure hypothetical events; the conditional marks projected hypothetical would-happen events; the indicative marks factual qualifications. Learn the mood with each conjunction as a single unit, and the family becomes manageable.