Phrases Conditionnelles: Vue d'Ensemble

A conditional sentence — une phrase conditionnelle — is a two-part sentence: one part introduces a condition, and the other states what follows from it. If it rains, I'll stay home. If I were rich, I'd buy a boat. If you had called me, I would have come. In French these sentences pivot on the conjunction si (if), and the tenses on either side of si must match a fixed pattern. There are exactly three productive types, plus a small set of mixed combinations, and the choice between them is a choice about how real or unreal the situation is.

This page is the sentence-level overview. It introduces the three types, lays down the single iron rule that governs them all, and walks through the most common errors English speakers make when carrying English conditionals over into French. For deeper treatment of each pattern — including stylistic variants, embedded conditionals, and the au cas où family — see the conditional sentences page in the complex grammar group.

The iron rule: no future and no conditional after si

Lock this in before anything else: after si, you may use only the présent, the imparfait, or the plus-que-parfait — never the futur, never the conditionnel.

A French teaching mnemonic captures it precisely: les si n'aiment pas les -rais — si doesn't like the -rais endings. The conditionnel endings (-rais, -rais, -rait, -rions, -riez, -raient) are forbidden in the si-clause. So is the future. Both sit only in the main clause.

Even native speakers of certain regional varieties occasionally produce si je serais; in standard French it is treated as a clear error and routinely circled in red on school papers. The rule is non-negotiable.

Type 1 — Real conditional: si + présent → futur

Pattern: si + présent, main clause in futur simple (or présent, or impératif).

Use Type 1 when the condition is genuinely possible. The speaker is not betting against it. If you come, I'll be happy — not because the speaker doubts you'll come, but because they're describing what will happen if you do.

The si-clause stays in the présent even though the event is in the future. This is one place where French and English happen to agree: English also says if you come, not if you will come. The mistake learners make is assuming this English logic applies everywhere — it does not, because quand-clauses go the other way (see verbs/future/si-with-present-not-future).

The main clause can also stay in the présent for general truths and routine consequences, or take the impératif for conditional commands:

Type 2 — Hypothetical: si + imparfait → conditionnel présent

Pattern: si + imparfait, main clause in conditionnel présent.

Use Type 2 when the condition is not currently true — or when the speaker treats it as unlikely. The imparfait here is not a past tense at all; grammarians call it the imparfait hypothétique or unreal imparfait. It signals that you have stepped into a hypothetical world.

The implicit reading is: I don't have more time. I'm not in your shoes. We don't live in Marseille. Type 2 is the workhorse of advice, daydreams, polite suggestions, and gentle hypotheticals. It also handles the standard what would you do if question:

A useful contrast with English: French uses the imparfait with the same form regardless of person. There is no French equivalent of the English subjunctive were in if I were rich. Si j'étais riche, si tu étais riche, s'il était riche — all the standard imparfait, no special form.

Type 3 — Counterfactual: si + plus-que-parfait → conditionnel passé

Pattern: si + plus-que-parfait, main clause in conditionnel passé.

Type 3 talks about something that did not happen. Both halves of the sentence are unreal: the condition was not met, and the consequence did not occur. This is the language of regret, alternative histories, and reproach.

The plus-que-parfait — avoir or être in the imparfait + past participle — is the standard tense in the si-clause. The conditionnel passé — avoir or être in the conditionnel + past participle — is the matching tense in the main clause. This is the most morphologically demanding of the three types because both halves use compound tenses, but the logic is identical to Type 2: take the Type 2 pattern and push both verbs one tense further into the past.

Type 3 is heavy with regret and reproach in conversation:

Mixed conditionals: Type 3 condition, Type 2 result

The three types above are the canonical ones, but real French speakers routinely mix them when the timing of the condition and the consequence don't line up. The most common mix is Type 3 in the si-clause and Type 2 in the main clause — a past unreal condition with a present consequence.

The condition refers to something that didn't happen in the past (tu n'as pas écouté); the consequence is a present-day state (tu es dans cette situation). Mix the tenses to fit: plus-que-parfait in the si-clause, conditionnel présent in the main clause.

The reverse mix — Type 2 condition with Type 3 consequence — is rarer but possible: Si tu étais plus prudent, tu n'aurais pas eu cet accident (If you were more careful, you wouldn't have had that accident). Here the condition is a stable trait and the consequence a past event.

Other conditional connectors

Si is the default, but a small set of other connectors introduce conditional meaning. Each has its own register and tense rules.

Au cas où + conditionnel — for precautionary reasoning ("just in case"):

Si jamais — emphatic si meaning "if by any chance":

À condition que / à moins que + subjonctif — sets a strict condition or exception:

These deserve their own page; the takeaway here is that si is not the only game in town, and that au cas où takes the conditionnel — directly contradicting the iron rule for si. The rule is specifically about si, not about all conditional connectors.

Drilling the patterns

The fastest way to internalize the three types is to take a single thought and run it through all three:

Notice the morphology shifts:

• viens / venais / étais venu — présent → imparfait → plus-que-parfait
• je serai / je serais / j'aurais été — futur → conditionnel présent → conditionnel passé

The si-clause moves leftward (further into the past) by one tense at each step; the main clause shifts from indicative future to conditional and then to compound conditional. The pairing is what carries the meaning, not the individual tenses.

Common Mistakes

Key Takeaways

French conditional sentences pivot on si and come in three productive types: Type 1 (real, si + présent → futur), Type 2 (hypothetical, si + imparfait → conditionnel présent), and Type 3 (counterfactual, si + plus-que-parfait → conditionnel passé). Mixed types — most commonly Type 3 in the si-clause with Type 2 in the main clause — handle situations where the condition and consequence don't share the same time. The single iron rule binding all of them: si never takes the futur or the conditionnel. Other conditional connectors (au cas où, à condition que) follow different rules, but si, the workhorse, follows the three-type pattern faithfully.