Conditional Sentences (Si clauses) in French

Overview

Conditional sentences, or phrases conditionnelles, are "if-then" constructions that let you express possibilities, hypothetical situations, and their consequences. They are built around the word si (if) and follow strict tense-pairing rules that are essential to master at the B1 level.

French has several types of conditional sentences, each expressing a different degree of likelihood. The two most important at B1 are the first conditional (real/possible situations) and the second conditional (unreal/hypothetical present situations). These correspond roughly to "If you come, I'll be happy" and "If I had time, I would travel."

The golden rule of si clauses in French is simple but absolute: never put the future or conditional tense directly after si. This is one of the most important grammar rules in French.

How It Works

Type 1: Real/possible condition

Si + present --> future / present / imperative

Si clause	Result clause	Example
Si + present	Futur simple	Si tu viens, je serai content.
Si + present	Present	Si tu viens, on mange ensemble.
Si + present	Imperatif	Si tu as faim, mange!

Type 2: Unreal/hypothetical present condition

Si + imparfait --> conditionnel present

Si clause	Result clause	Example
Si + imparfait	Conditionnel	Si j'avais le temps, je viendrais.

Other conditional expressions

Expression	Meaning	Example
si jamais	if ever / if by chance	Si jamais tu le vois, dis-lui bonjour.
au cas ou + conditionnel	in case	Au cas ou tu aurais besoin...
meme si + indicative	even if	Meme si tu viens, ca ne changera rien.
a condition que + subjunctive	on the condition that	A condition qu'il fasse beau...

Examples in Context

French	English	Note
Si tu viens, je serai content.	If you come, I'll be happy.	Type 1: real possibility
Si j'avais le temps, je viendrais.	If I had time, I would come.	Type 2: hypothetical
Si j'etais riche, j'acheterais une maison.	If I were rich, I would buy a house.	Type 2: unreal present
Au cas ou tu aurais besoin...	In case you need...	Au cas ou + conditional
Si tu as froid, mets un pull.	If you're cold, put on a sweater.	Type 1: present + imperative
Si je pouvais, je t'aiderais.	If I could, I would help you.	Type 2: ability
Si on allait au cinema?	How about going to the cinema?	Si + imparfait for suggestion
Meme si je suis fatigue, je viendrai.	Even if I'm tired, I'll come.	Meme si + indicative
Si jamais il appelle, previens-moi.	If he happens to call, let me know.	Si jamais + present
Si j'etais toi, je ne ferais pas ca.	If I were you, I wouldn't do that.	Advice formula
S'il fait beau, on ira a la plage.	If it's nice out, we'll go to the beach.	Type 1 with weather
Si tu veux, on peut rester.	If you want, we can stay.	Type 1: present + present

Common Mistakes

Putting the future or conditional after si

• Wrong: Si je serai libre, je viendrai.
• Right: Si je suis libre, je viendrai.
• Why: This is the cardinal rule: after si (meaning "if"), never use the future or conditional tense. Use the present for real conditions, the imparfait for hypothetical ones.

Mixing up the two conditional types

• Wrong: Si j'ai le temps, je viendrais. (mixing present with conditional)
• Right: Si j'ai le temps, je viendrai. (Type 1) or Si j'avais le temps, je viendrais. (Type 2)
• Why: The tenses must match their type: si + present goes with future; si + imparfait goes with conditional. Don't mix them.

Confusing si (if) with si (whether) for tense rules

• "If": Si tu viens... (no future after si)
• "Whether": Je ne sais pas s'il viendra. (future is allowed because si means "whether")
• Why: The no-future-after-si rule only applies when si means "if" (condition), not when it means "whether" (indirect question).

Forgetting that si + il = s'il

• Wrong: Si il vient...
• Right: S'il vient...
• Why: Si always elides before il and ils: s'il, s'ils. But not before elle: si elle.

Usage Notes

The si + imparfait construction has a secondary use as a polite suggestion, equivalent to "How about...?":

• Si on allait au restaurant? (How about going to a restaurant?)
• Si tu venais avec nous? (How about coming with us?)

This is very common in spoken French and is an elegant way to make suggestions without being directive.

Au cas ou always takes the conditional, never the subjunctive: Au cas ou il pleuvrait... (In case it rains...). This is a useful alternative to si for expressing precautionary conditions.

In spoken French, the result clause sometimes uses the futur proche instead of the futur simple in Type 1: Si tu viens, on va manger ensemble. This is perfectly natural and increasingly common.

Note that meme si (even if) takes the indicative, while meme que does not exist. Do not confuse it with bien que (although), which takes the subjunctive.

Practice Tips

1. Write five Type 1 sentences about real plans: Si j'ai le temps demain... Si il fait beau ce weekend... Then rewrite each as a Type 2 hypothetical: Si j'avais le temps... S'il faisait beau...
2. Practice the suggestion formula Si on + imparfait? by proposing five activities: Si on allait au cinema? Si on prenait un verre? Si on partait en voyage?
3. When you catch yourself wanting to put a future tense after si, stop and rethink. Drill the rule until it becomes automatic: si = present or imparfait, never future or conditional.

Related Concepts

• Present Conditional -- the tense used in the result clause of Type 2 conditionals