When you start learning French, you quickly come across a key structure: conditional sentences. These are the sentences we use to express a condition and its result—in other words, to talk about what happens, what could happen, or what might have happened under different circumstances.

This is a very common pattern in everyday language. We use it to make suggestions, give advice, imagine alternatives, or reflect on things that didn’t go as planned. That’s why it’s important to understand how it works from the very beginning.

For English-speaking learners, the main challenge is not so much the meaning as the choice of verb tenses. In French, these structures follow a clear and consistent logic—but it’s not the same as in English. It’s very tempting to translate word for word, and that’s where mistakes often come from.

In fact, everything depends on one key idea: how real the situation is. Depending on whether the condition is real, hypothetical, or already finished in the past, French uses different tenses in a very systematic way.

In this guide, we’ll look at how French conditional sentences are built, which tenses to use, and how to tell the different structures apart.

1. What is a conditional sentence?

A conditional sentence has two parts: a clause expressing the condition (introduced by si, meaning “if”), and a main clause expressing the result.

Let’s look at a simple example:

– Si tu prends le métro, tu éviteras les embouteillages.

In this sentence, the first part (“if you take the metro”) introduces the condition, while the second (“you’ll avoid traffic”) expresses the result.

The structure itself doesn’t change. What changes is the verb tense—and that choice reflects how real or hypothetical the situation is.

2. When the situation is real or possible

The first type covers situations that are considered real, possible, or likely to happen. In this case, we are not imagining something hypothetical—we are describing a realistic outcome.

In French, this structure is very consistent: the si-clause uses the present tense, while the main clause can take the present, the future, or the imperative, depending on the context.

The structure is:

si + présent → présent / futur / impératif

– Si tu prends le métro, tu évites les embouteillages.

– Si nous allons en France cet été, nous visiterons l’Alsace.

– Si tu aimes vraiment cette voiture, achète-la !

In all these examples, the condition is realistic and the result is presented as a natural consequence. This is what distinguishes this type from more hypothetical structures.

3. When the situation is hypothetical in the present

The second type covers situations that are not true at the moment of speaking, or that are unlikely to happen. Here, we move away from reality and into hypothetical or imagined situations.

In French, this type follows a very clear structure: the si-clause uses the imparfait, while the main clause uses the conditionnel présent.

The structure is:

si + imparfait → conditionnel présent

– Si tu étais plus gentille avec ton frère, il ne pleurerait pas tout le temps.

– Si tu me prêtais ton sac, cela me ferait très plaisir.

These sentences describe a situation that is different from reality. It’s important to understand that the imparfait here does not express past time—it simply signals that the condition is hypothetical.

This is similar to English sentences like “If I were…” or “If you had more time…”, although the tense system works differently in French.

4. When the situation refers to the past

The third type deals with hypothetical situations in the past. In this case, we are talking about something that did not happen and cannot be changed.

These sentences are often used to express regret, missed opportunities, or speculation about how things might have turned out differently.

In French, the structure uses the plus-que-parfait in the si-clause and the conditionnel passé in the main clause.

The structure is:

si + plus-que-parfait → conditionnel passé

– Si Philippe m’avait avertie à temps, je serais allée le chercher à la gare.

– Si leurs conditions de travail avaient été meilleures, ils n’auraient pas fait grève.

What matters here is the idea of finality: the situation belongs entirely to the past and cannot be changed. This is what distinguishes it from present hypotheticals.

5. A quick overview

To use these structures correctly, it helps to focus on one key idea: the type of situation you are describing.

If the condition is real or possible, use the present after si.

If the situation is hypothetical in the present, use the imparfait.

If the situation refers to the past and cannot be changed, use the plus-que-parfait.

So the three core structures are:

• si + présent → présent / futur / impératif
• si + imparfait → conditionnel présent
• si + plus-que-parfait → conditionnel passé

With regular practice, these structures become intuitive, allowing you to build sentences naturally without relying on translation.

6. Why mastering these structures matters

Conditional sentences are part of everyday communication. We use them all the time—often without even noticing—to make suggestions, imagine alternatives, give advice, or talk about what we wish we had done.

Because they’re so common, they’re also a clear indicator of your level. Using them correctly makes your French sound more natural, precise, and fluent.

7. Want a clear and simple summary?

If you’d like a handy reference, you can check the grammar sheet Les propositions subordonnées de condition in the Sillabi resources.

In addition to conditional sentence structures, Sillabi’s grammar resources also help you review the verb tenses needed to build them correctly, so you can clear up any doubts and use them with more confidence.

8. Want to use these structures naturally?

Understanding the rules is essential—but it’s not enough. To use these structures naturally, you need practice, context, and consistency.

The Et voilà! course is designed to guide you through that process: it helps you turn grammar into a practical tool for real communication, with guided activities and step-by-step explanations.

And if you’re not sure where to start, you can take the placement test—in just a few minutes, you’ll find out which level is right for you.