Passé Composé vs Imparfait: The Rule That Finally Sticks

Passé composé is what happened. Imparfait is what was going on around it.

That is the whole rule, and you have probably read it before. The reason passé composé vs imparfait still catches you out at B1 is not that the rule is hard. It is that six specific situations break it, and most explanations stop before they get there. This page covers the rule in one line, then spends the rest of its time on the six.

What is the difference between passé composé and imparfait?

Passé composé expresses a completed event: something happened, it finished, and the story moves on. Imparfait expresses the situation that event happened inside: a description, a habit, or an action still in progress.

The Office québécois de la langue française puts the imparfait side precisely: it evokes an action in progress, where part of the action is complete and part is still to come. The passé composé does the opposite. It marks a finished action whose result is tied to the present moment.

So:

• J'ai mangé une pizza. One event, finished.
• Il faisait froid. The situation, no start and no end in view.

Say the two sentences out loud and notice that the second one feels unfinished. That feeling is the tense doing its job.

Why do words like "hier" and "souvent" not decide the tense?

Time words are a hint, not a rule. They correlate with one tense or the other often enough to be taught as triggers, and then they fail on the sentences you actually want to build.

Souvent usually pulls imparfait because repeated things tend to be background. But j'ai souvent pensé à toi is correct passé composé: a set of occasions, treated as one closed block. Hier usually pulls passé composé, and hier, il pleuvait is correct imparfait: yesterday is when the weather was happening, not an event that finished.

The question is never which adverb is in the sentence. It is whether you are naming an event or painting a situation.

What happens when one past action interrupts another?

Use imparfait for the action already running and passé composé for the thing that cut into it. This is the single most reliable pattern in French past narration, and it is worth learning as a shape rather than a rule.

The OQLF's own example is Marc montait les escaliers quand Isabelle l'a appelé. Marc was already on the stairs, that is the imparfait, and the phone call landed in the middle of it, that is the passé composé. English marks the same contrast with "was climbing" against "called".

Once you can hear which half of a sentence is the setting, most of your tense choices make themselves. It is the same instinct the rest of B1 runs on, and it sits inside the wider French grammar syllabus.

Which French verbs change meaning between the two tenses?

Six common verbs mean genuinely different things depending on the tense, because the passé composé turns a state into the moment that state began. The University of Texas at Austin's French grammar states the principle: verbs like être, avoir, pouvoir, vouloir and savoir usually sit in the imparfait because they describe a state, but in the passé composé they indicate a change of state.

This is the table to keep. Nothing else on this page is worth memorising as a list.

Read the right-hand column again. Every one of them is a moment, not a condition. All six are drilled with their answer key in Le Français Pas à Pas, which explains why you were right or wrong rather than just marking it. J'ai su la vérité is not "I knew the truth", it is the second you found out.

Why does "depuis" force the imparfait?

Because depuis measures something that was still going when the past event arrived, and only the imparfait can leave an action open. In English this comes out as "had been doing", which is why translating word by word sends you to the wrong tense.

Tex's French Grammar gives the pattern with depuis and the imperfect: Tammy attendait Tex depuis une heure quand il est entré, "Tammy had been waiting for Tex for an hour when he came in". The waiting had not stopped when he walked in. Put a attendu there and you have closed the waiting before the arrival, which is a different story.

How do you tell a whole story, not just one sentence?

Set the scene in imparfait, then run the events in passé composé, and let the two alternate. A French past narrative is not one tense with occasional exceptions, it is two tracks running at once.

Il faisait beau. Les oiseaux chantaient. Soudain, j'ai vu un cerf. Two lines of setting, then one event. If you narrate entirely in passé composé you get a list. If you narrate entirely in imparfait, nothing ever happens.

The habit case belongs to the setting track too. The OQLF notes that the imparfait also expresses repetition or habit, as in Francine nageait trois fois par semaine. Three times a week for how long? Unspecified, and that is the point.

Where does this actually break down for learners?

It almost never breaks on the rule itself. It breaks on the order the two tenses are learned in, and the damage is done a whole level before anyone reaches this contrast.

Passé composé arrives first, at A2, as the way to talk about the past. It works. You narrate with it for months and nothing visibly breaks, so it quietly becomes the default. Imparfait turns up a few items later, taught as description and habit, and by then it is competing against a tense you already trust. Our own curriculum tracks the consequence twice, at two different levels: using passé composé for background description is a signature error at A2, and it returns at B1 as all-passé-composé narration. Same habit, one level older and harder to shift.

The second failure is subtler, and it is caused by teaching. Learners who were given trigger words, soudain for one tense and souvent for the other, do well on exercises and then freeze on their own sentences. The triggers work because exercise sentences are built around them. Your own sentences are not. That is why the section above spends its time on what kind of thing you are describing rather than on which adverb is present.

If you recognise yourself in either of those, the fix is not another rule. It is deciding whether you are naming an event or painting a situation, before you conjugate anything.

What level is this, and what comes after it?

This is B1, and in our own curriculum it is the first item at that level, listed as the pivotal contrast of the whole stage. The signature error we track is exactly the one above: narrating everything in passé composé, and missing the j'ai su against je savais shift.

What comes next builds directly on it. Plus-que-parfait needs you to already hear the two tracks, because it sets an event before the one you are narrating, and it is one of the eight tenses you actually have to produce. Si clauses type 2 need the imparfait as a form before they can use it as a hypothesis. Get this contrast solid and the rest of B1 stops feeling like separate rules. If you are not sure whether you are at B1 yet, the placement test will tell you where to start, and the self-study library runs the levels in order from there.