Comme si: The 'As If' Construction with Imparfait and Plus-que-parfait | French Grammar

The construction comme si — "as if" — is one of those pieces of French where the grammatical pattern is fixed and unforgiving, but the underlying logic is identical to a system you already know. Comme si always introduces a counterfactual: the speaker is comparing the actual situation to one that is not real. Because the comparison is unreal, French uses tenses that mark unreality — the imparfait for present-counterfactual comparisons, the plus-que-parfait for past-counterfactual ones. The conditionnel, despite what English-speaking learners constantly want to put there, is never the right answer.

This page maps the two patterns, explains why the conditionnel is excluded, and shows how comme si slots into the broader French system of unreality marking.

The two patterns at a glance

The pattern is simple, and it parallels the si-clause system:

Type of comparison	Tense after comme si	Example
Present-counterfactual	imparfait	Il fait comme s'il savait. (He acts as if he knew — but he doesn't.)
Past-counterfactual	plus-que-parfait	Il a parlé comme s'il avait été là. (He spoke as if he had been there — but he wasn't.)

The main verb of the sentence (the one outside the comme si clause) can be in any tense — present, past, future, conditional. What matters is the tense inside the comme si clause: imparfait or plus-que-parfait, period.

Comme si + imparfait: present counterfactual

The most common form. The imparfait inside comme si describes a state or action that is being imagined as a comparison point — as if this were the case. The actual situation, of course, is something else.

Il me parle comme si j'étais un enfant de cinq ans.

He speaks to me as if I were a five-year-old child.

Elle se comporte comme si rien ne la dérangeait, mais on voit bien qu'elle est blessée.

She acts as if nothing bothered her, but you can clearly see she's hurt.

Tu fais comme si tu ne me connaissais pas, c'est ridicule.

You're acting as if you didn't know me, it's ridiculous.

Il pleut comme s'il y avait une mousson.

It's raining as if there were a monsoon.

The mood and the meaning come together cleanly: the imparfait places the imagined situation in a non-actual frame (the same frame it occupies inside si-clauses for hypothetical conditions), and the comparison is read as counterfactual.

A close cousin: comparison without falsehood

Sometimes comme si + imparfait reads less as a counterfactual and more as a vivid comparison — as if signaling a strong resemblance, not a contradiction.

Il a mangé comme s'il n'avait pas vu de nourriture depuis des jours.

He ate as if he hadn't seen food for days. (Maybe he genuinely hadn't — but the form is the same.)

Elle me regardait comme si elle voulait me dire quelque chose d'important.

She was looking at me as if she wanted to tell me something important.

The grammatical pattern is the same; only the speaker's stance shifts. Whether the comparison is truly false or just emphatically resemblance, French marks it with imparfait.

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The comme si + imparfait construction is the unmarked counterfactual comparison in French — the bread-and-butter form. Use it whenever English would say "as if" + simple past ("as if he knew", "as if it were"). The match is exact.

Comme si + plus-que-parfait: past counterfactual

When the imagined comparison sits in the past — as if something had happened that didn't, or as if a past situation had been other than it was — French uses the plus-que-parfait. The plus-que-parfait is built from the imparfait of avoir or être + the past participle: j'avais fait, j'étais venu. It's the natural counterpart of the imparfait when you need to push the unreality one step further back in time.

Il a parlé de Paris comme s'il y avait vécu pendant des années, mais en fait il n'y a passé qu'un week-end.

He spoke about Paris as if he had lived there for years, but actually he only spent one weekend there.

Elle est rentrée à la maison comme si rien ne s'était passé.

She came home as if nothing had happened.

Le serveur s'est excusé comme s'il avait oublié notre commande, alors qu'il l'avait juste mal lue.

The waiter apologized as if he had forgotten our order, when in fact he had just misread it.

Tu agis comme si tu n'avais jamais entendu parler de cette histoire.

You're acting as if you'd never heard of this business.

The pairing is clean: imparfait for now-or-general counterfactuals, plus-que-parfait for then-counterfactuals. Both are imperfect — that is, they're built on the imperfect stem (j'avais in plus-que-parfait literally is the imparfait of avoir). The whole comme si system lives inside the imparfait family.

Mixed timelines

The main verb and the comme si clause don't have to share a timeline. Each tense answers a separate question.

Il marche comme s'il avait couru un marathon.

He walks as if he had run a marathon. (Present main clause + past counterfactual inside comme si.)

Elle parlait de ses voisins comme s'ils étaient ses ennemis.

She used to talk about her neighbors as if they were her enemies. (Past habitual main clause + present counterfactual inside comme si.)

Tu te tiendras comme si tu savais ce que tu fais.

You'll act as if you knew what you're doing. (Future main clause + present counterfactual.)

The main clause's tense reports when the speaking, acting, or comparing happens; the comme si tense reports the relationship between the imagined situation and the moment of comparison.

Why the conditionnel is forbidden

This is the rule English speakers most often break, because in English we say "as if he would understand" or "as if he could see us." The conditional creeps into the comme si clause from English, and it is wrong every time.

❌ Comme si tu pourrais comprendre.

Wrong — *comme si* never takes the conditionnel.

✅ Comme si tu pouvais comprendre.

As if you could understand.

The reason is structural. The same prohibition applies inside si-clauses for ordinary hypotheticals:

Si j'avais le temps, je viendrais. — imparfait inside si, conditionnel in the main clause.
❌ Si j'aurais le temps, je viendrais. — wrong, conditionnel inside si.

French splits the work cleanly: the conditionnel goes in the consequence clause, and the imparfait (or plus-que-parfait) goes in the condition clause. Comme si is a condition — an imagined backdrop — so it must take the imparfait or plus-que-parfait, not the conditionnel. The system is symmetric: where English uses the same modal "would" twice (and thereby muddies the grammar), French uses two different forms to keep condition and consequence distinct.

The si / comme si prohibition on the conditionnel is sometimes summarized as a slogan French students memorize: « Les si n'aiment pas les rais » — "the si*s don't like the -raises" — referring to the conditionnel endings -rais, -rait, -raient*.

Comparison with the si-clause system

The parallel between si and comme si is exact, and seeing it makes the comme si rule feel inevitable rather than arbitrary.

Construction	Subordinate clause	Main clause	Reading
si + present	présent	présent / futur	open condition (Type 1)
si + imparfait	imparfait	conditionnel présent	hypothetical condition (Type 2)
si + plus-que-parfait	plus-que-parfait	conditionnel passé	past counterfactual (Type 3)
comme si + imparfait	imparfait	any tense	present counterfactual comparison
comme si + plus-que-parfait	plus-que-parfait	any tense	past counterfactual comparison

Comme si slots into the bottom rows of the si system. The same tenses do the same modal work — marking unreal conditions — and the same prohibition on the conditionnel applies. If you've internalized si j'avais ... je viendrais, the comme si pattern is the same logic applied to comparisons rather than consequences.

Comparison with English

English maps onto French comme si with reasonable cleanness:

as if
- simple past (as if he knew, as if it were so) → comme si
  - imparfait.
as if
- past perfect (as if he had known, as if she had been there) → comme si
  - plus-que-parfait.

The trap is the use of "would" or "could" in English. Many English speakers say "as if he would understand" without realizing it's a colloquial extension of the basic "as if he understood." French has no parallel form, and the conditionnel inside comme si is impossible.

A second trap is the English "as if I were" / "as if I was." English allows the past indicative (was) or the past subjunctive (were) — both work. French has only one form for être: j'étais, tu étais, il était — these are the imparfait. There is no separate subjunctive imperfect in everyday French. (A literary form, fusse, exists but is rare; see the verb-reference page on être.)

Il agit comme s'il était un expert.

He acts as if he were an expert. / He acts as if he was an expert. (One French form, two English options.)

A few stylistic notes

Comme si with deletion

In conversation, comme si sometimes appears as a complete utterance, with the subordinate verb left implicit:

— Tu crois qu'il va t'écouter ? — Comme si !

— Do you think he'll listen to you? — As if!

This is the same exclamatory as if as English. It's idiomatic, not formal, and the missing verb is mentally supplied by context.

On dirait que and on aurait dit que

Closely related to comme si are the idioms on dirait que (it looks like / it sounds like / one would say that) and its past form on aurait dit que (it looked like). These use the conditionnel of the main verb (dire) rather than inside the subordinate, so they don't break the comme si rule:

On dirait qu'il va pleuvoir.

It looks like it's going to rain.

On aurait dit qu'il avait vu un fantôme.

You'd have thought he'd seen a ghost.

The que clause here takes the indicative or the plus-que-parfait, depending on timeline. On dirait que is structurally different from comme si but covers similar conversational ground.

Faire comme si

The fixed expression faire comme si (to act as if, to pretend) deserves a mention. It's the most colloquial way to say someone's putting on a show:

Il fait comme si tout allait bien, mais il est clairement effondré.

He pretends as if everything's fine, but he's clearly devastated.

Arrête de faire comme si tu n'avais rien entendu.

Stop pretending as if you hadn't heard anything.

The pattern follows the same rules as plain comme si: imparfait for present-counterfactual, plus-que-parfait for past-counterfactual.

Common Mistakes

Mistake 1: Using the conditionnel after comme si.

❌ Il fait comme s'il saurait.

Wrong — *comme si* never takes the conditionnel. The futur stem of *savoir* (*saur-*) plus the conditionnel ending is structurally banned here.

✅ Il fait comme s'il savait.

He acts as if he knew.

Mistake 2: Using the present indicative instead of the imparfait.

❌ Il me parle comme si je suis un enfant.

Wrong — the comparison is unreal, so *suis* must shift to the imparfait *étais*.

✅ Il me parle comme si j'étais un enfant.

He speaks to me as if I were a child.

Mistake 3: Using the passé composé instead of the plus-que-parfait for past counterfactuals.

❌ Elle a parlé comme s'il a été là.

Wrong — past counterfactuals require the plus-que-parfait, not the passé composé. *A été* must become *avait été*.

✅ Elle a parlé comme s'il avait été là.

She spoke as if he had been there.

Mistake 4: Forgetting to elide si before il.

❌ comme si il savait

Wrong — *si* elides before *il* and *ils*: *s'il*, *s'ils*. Other vowels do not trigger elision: *comme si elle*, *comme si on*, *comme si Anne*.

✅ comme s'il savait

as if he knew

Mistake 5: Using the subjunctive after comme si.

❌ Comme si tu sois fatigué.

Wrong — *comme si* takes the imparfait or plus-que-parfait, never the subjunctive.

✅ Comme si tu étais fatigué.

As if you were tired.

Key takeaways

The comme si construction in French has just two patterns: imparfait for present-counterfactual comparisons (comme s'il savait) and plus-que-parfait for past-counterfactual ones (comme s'il avait été là). The main clause can be in any tense; only the subordinate clause is constrained.

The conditionnel is structurally banned inside comme si, just as it is inside ordinary si-clauses. The « les si n'aiment pas les rais » slogan covers both. English speakers often want to translate "would" or "could" into the conditionnel; resist the urge and use the imparfait or plus-que-parfait instead.

Memorize a handful of comme si expressions as units (comme s'il avait vu un fantô me, comme si rien ne s'était passé, fais comme si de rien n'était) and the pattern will become second nature. Notice the elision comme s'il and comme s'ils — these are the only environments where si is reduced; comme si elle, comme si on, comme si Anne keep the full form.

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