The Construction “Il faut + Infinitive”｜Rules and Advanced Usage

In French, when you want to say “one must…” or “it is necessary to…”, a very common expression is “Il faut + infinitive”. This structure is not only simple and easy to use but also appears frequently in everyday life.

In this lesson, I will explain the meaning of the construction “Il faut + infinitive”, along with examples of common verbs used in this pattern.

1. The Basics of the Il faut + infinitive Construction

1-1. Expressing Necessity (It is necessary to…)

In French, Il faut corresponds to English expressions such as “It is necessary to” or “You must”. It expresses a general obligation or necessity.

By placing an infinitive verb after Il faut, the sentence expresses “It is necessary to do (something).”

1-2. “Il” as an Impersonal Subject

The subject Il in this construction does not refer to any specific person or thing. It is an impersonal subject used to complete the grammatical structure.

When translating into English or Japanese, Il is not rendered as “it,” but the sentence is instead expressed naturally as “one must…” or “it is necessary to…”.

1-3. “faut” as the Third-Person Singular of falloir

The word faut comes from the verb falloir (to be necessary), conjugated in the third person singular.

This verb is used exclusively in the construction “Il faut + infinitive”. The subject is always Il and never changes.

2. The Infinitive Expresses the Required Action

After Il faut, an infinitive verb follows, indicating the action that is necessary. A wide variety of verbs can be used in this structure:

Frequently used verbs include faire (to do), prendre (to take), avoir (to have), and aller (to go).

3. The Negative Form: Il ne faut pas + infinitive

To negate Il faut, simply place ne … pas around the verb faut. This expresses prohibition or the absence of necessity.

In this way, the structure is used effectively for expressing rules, prohibitions, or warnings.

4. Use with Reflexive Verbs

Reflexive verbs can also appear in this construction.

Here, se lever is a reflexive verb meaning “to get up,” literally implying “someone must get themselves up.” The reflexive pronoun se is always used in its third-person singular form, regardless of the subject.

5. Adding Purpose or Reason

The “Il faut + infinitive” structure can be expanded by adding a purpose or reason.

Here, “pour + infinitive” adds purpose, while adverbs such as bien refine the action.

6. Summary

泉（Izumi）

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