The usual French translation of “What is it?” is Qu’est-ce que c’est ? In everyday speech, French speakers often say C’est quoi ? instead. The best choice depends on the setting, the tone, and what “it” means in context.

The standard expression

Qu’est-ce que c’est ? “What is it?”

This is the safest and most common form. It works in both speech and writing and does not sound too formal or too casual.

• Qu’est-ce que c’est ? “What is it?”
• Qu’est-ce que c’est, ce bruit ? “What is that noise?”
• Qu’est-ce que c’est sur la table ? “What is that on the table?”
• Qu’est-ce que c’est exactement ? “What exactly is it?”
• Tu sais ce que c’est ? “Do you know what it is?”
• Vous savez ce que c’est ? “Do you know what it is?”

The phrase can refer to a thing, a sound, a smell, an event, or a situation.

• Qu’est-ce que c’est, cette odeur ? “What is that smell?”
• Qu’est-ce que c’est, cette lumière ? “What is that light?”
• Qu’est-ce que c’est, cette histoire ? “What is this story about?”
• Qu’est-ce que c’est, ce document ? “What is this document?”

The common spoken form

C’est quoi ? “What is it?”

This is very common in everyday speech. It is informal, but not rude by itself.

• C’est quoi ? “What is it?”
• C’est quoi, ce truc ? “What is this thing?”
• C’est quoi, ton idée ? “What is your idea?”
• C’est quoi, ce bouton ? “What is this button?”
• C’est quoi, cette application ? “What is this app?”
• C’est quoi, le problème ? “What is the problem?”

You can use c’est quoi ? with friends, family, classmates, and people you know well. In a formal letter, a work meeting, or a careful presentation, qu’est-ce que c’est ? is usually better.

Asking about something you can see

Both Qu’est-ce que c’est ? and C’est quoi ? can mean “What is this?” or “What is that?” French does not always mark the difference between “this” and “that” in this question.

• Qu’est-ce que c’est ? “What is this?”
• Qu’est-ce que c’est là-bas ? “What is that over there?”
• C’est quoi, ça ? “What is that?”
• C’est quoi, ceci ? “What is this?”
• C’est quoi, cela ? “What is that?”

The words ça, ceci, and cela make the reference more exact:

• Ça means “that” or “this” in everyday speech.
• Ceci means “this” and is more formal or written.
• Cela means “that” and is more formal than ça.

Examples:

• Qu’est-ce que c’est que ça ? “What is that?”
• Qu’est-ce que c’est que ceci ? “What is this?”
• Qu’est-ce que c’est que cela ? “What is that?”

Asking with surprise or strong feeling

Qu’est-ce que c’est que ça ? “What is that?”

This form often shows surprise, shock, anger, or confusion. The tone matters.

• Qu’est-ce que c’est que ça ? “What is that?”
• Qu’est-ce que c’est que ce bruit ? “What is that noise?”
• Qu’est-ce que c’est que cette tache ? “What is this stain?”
• Qu’est-ce que c’est que cette histoire ? “What is this story?”
• Qu’est-ce que c’est que ce désordre ? “What is this mess?”

A softer version is:

• Qu’est-ce que c’est, ça ? “What is that?”

A stronger, more annoyed version is:

• C’est quoi, ça ? “What is that?”

The same words can sound calm, curious, or angry depending on the speaker’s voice.

Asking about a subject or matter

When “What is it?” means “What is the matter?” or “What is this about?”, use a phrase that points to the subject rather than the object.

De quoi s’agit-il ? “What is it about?” or “What is it?”

This is formal and common in writing, official speech, customer service, and serious discussion.

• De quoi s’agit-il ? “What is it about?”
• De quoi s’agit-il exactement ? “What exactly is it about?”
• De quoi s’agit-il dans ce rapport ? “What is this report about?”
• De quoi s’agit-il dans cette affaire ? “What is this case about?”
• Pouvez-vous m’expliquer de quoi il s’agit ? “Can you explain what it is about?”

In ordinary speech, French speakers often use:

• C’est quoi, exactement ? “What is it exactly?”
• Ça parle de quoi ? “What is it about?”
• Ça concerne quoi ? “What does it concern?”
• C’est à propos de quoi ? “What is it about?”

Examples:

• Ça parle de quoi, ce film ? “What is this film about?”
• C’est à propos de quoi, la réunion ? “What is the meeting about?”
• Ça concerne quoi, ce formulaire ? “What does this form concern?”
• De quoi parle ce livre ? “What is this book about?”

Asking what something means

Sometimes English speakers use “What is it?” when they really mean “What does it mean?” In French, use qu’est-ce que ça veut dire ?

Qu’est-ce que ça veut dire ? “What does it mean?”

• Qu’est-ce que ça veut dire ? “What does it mean?”
• Qu’est-ce que ce mot veut dire ? “What does this word mean?”
• Qu’est-ce que cette phrase veut dire ? “What does this sentence mean?”
• Ça veut dire quoi ? “What does it mean?”
• Que veut dire ce symbole ? “What does this symbol mean?”

Ça veut dire quoi ? is the usual informal form. Que signifie… ? is more formal and is common in writing.

• Que signifie ce mot ? “What does this word mean?”
• Que signifie cette expression ? “What does this expression mean?”

Do not normally translate “What is it?” as Qu’est-ce que c’est ? when you are asking for the meaning of a word, sign, or phrase.

Asking what kind of thing it is

To ask about the type or nature of something, use qu’est-ce que c’est comme… ? or ask directly about its type.

• C’est quoi comme voiture ? “What kind of car is it?”
• Qu’est-ce que c’est comme film ? “What kind of film is it?”
• C’est quel genre de musique ? “What kind of music is it?”
• De quel type de problème s’agit-il ? “What type of problem is it?”
• Quelle sorte de plante est-ce ? “What kind of plant is it?”

The phrase c’est quoi comme… ? is informal and common in conversation.

• C’est quoi comme téléphone ? “What kind of phone is it?”
• C’est quoi comme gâteau ? “What kind of cake is it?”
• C’est quoi comme maladie ? “What kind of illness is it?”

Asking about a person

For a person, English “What is it?” is usually not the right model. Use qui est-ce ? or another phrase with qui.

Qui est-ce ? “Who is it?”

• Qui est-ce ? “Who is it?”
• Qui est-ce sur la photo ? “Who is that in the photo?”
• C’est qui ? “Who is it?”
• C’est qui, cette personne ? “Who is this person?”
• Qui est cette femme ? “Who is this woman?”

Use qui for people and qu’est-ce que for things.

• Qui est-ce ? “Who is it?”
• Qu’est-ce que c’est ? “What is it?”

At the door or on the phone, Qui est-ce ? can mean “Who is it?”

Asking what someone’s job or role is

English speakers may also use “What is it?” when asking what something is in a wider sense, such as a job, role, or condition. French uses a more exact question.

• Quel est son métier ? “What is his job?”
• Qu’est-ce qu’il fait dans la vie ? “What does he do for a living?”
• Quel est son rôle ? “What is his role?”
• C’est quoi, son travail ? “What is his job?”
• Quelle est sa fonction ? “What is his function or role?”

Asking about a past thing

Change c’est to c’était when the thing existed or happened in the past.

• Qu’est-ce que c’était ? “What was it?”
• C’était quoi ? “What was it?”
• Qu’est-ce que c’était que ce bruit ? “What was that noise?”
• De quoi s’agissait-il ? “What was it about?”
• Tu sais ce que c’était ? “Do you know what it was?”

Examples:

• J’ai entendu un bruit. Qu’est-ce que c’était ? “I heard a noise. What was it?”
• Il y avait une réunion hier. C’était quoi ? “There was a meeting yesterday. What was it?”
• De quoi s’agissait-il au juste ? “What exactly was it about?”

Formal and literary forms

Qu’est-ce ? “What is it?”

This is correct but rare in modern everyday French. It may sound literary, old-fashioned, or dramatic.

• Qu’est-ce ? “What is it?”
• Qu’est-ce donc ? “What is it, then?”
• Qu’est-ce donc que cette étrange machine ? “What, then, is this strange machine?”

Qu’est-ce donc ? is also literary or dramatic. It is not the normal choice for daily conversation.

A formal but natural choice is:

• De quoi s’agit-il ? “What is it about?”
• Pourriez-vous me dire ce que c’est ? “Could you tell me what it is?”
• Serait-il possible de savoir ce que c’est ? “Would it be possible to know what it is?”

Asking politely

The question itself is not usually rude, but the short forms can sound sharp in some settings. Add a polite phrase when speaking to a stranger or in a formal situation.

• Pouvez-vous me dire ce que c’est ? “Can you tell me what it is?”
• Pourriez-vous m’expliquer ce que c’est ? “Could you explain what it is?”
• Est-ce que vous savez ce que c’est ? “Do you know what it is?”
• Savez-vous ce que c’est ? “Do you know what it is?”
• Excusez-moi, qu’est-ce que c’est ? “Excuse me, what is it?”

The formal vous form is used with strangers, customers, older people, and in many work settings.

Word order and register

French has several ways to form questions. For this expression, the main choices are:

• Qu’est-ce que c’est ? “What is it?”
• C’est quoi ? “What is it?”
• De quoi s’agit-il ? “What is it about?”

The first is neutral. The second is informal. The third is formal and often asks about a matter or topic.

The form Que c’est ? is not correct as a normal modern question. The form Qu’est-ce que c’est ? is correct.

The form Qu’est-ce que cela est ? is grammatical in a narrow sense but sounds stiff and unnatural in most settings. Use Qu’est-ce que c’est ? instead.

Common examples by situation

You see an unknown object

• Qu’est-ce que c’est ? “What is it?”
• C’est quoi, cet objet ? “What is this object?”
• Tu sais ce que c’est ? “Do you know what it is?”
• De quoi s’agit-il ? “What is it?”

You hear an unknown sound

• Qu’est-ce que c’est, ce bruit ? “What is that noise?”
• C’est quoi, ce bruit ? “What is that noise?”
• Qu’est-ce que c’était ? “What was that?”
• Tu sais ce que c’était ? “Do you know what that was?”

You see something strange

• Qu’est-ce que c’est que ça ? “What is that?”
• C’est quoi, ça ? “What is that?”
• Qu’est-ce que c’est, cette chose ? “What is this thing?”
• Mais qu’est-ce que c’est que ça ? “What on earth is that?”

You ask about a film, book, or event

• De quoi s’agit-il ? “What is it about?”
• Ça parle de quoi ? “What is it about?”
• C’est quoi, ce film ? “What is this film about?”
• De quoi parle ce livre ? “What is this book about?”
• Quel est le sujet ? “What is the subject?”

You ask about a word or phrase

• Qu’est-ce que ça veut dire ? “What does it mean?”
• Ça veut dire quoi ? “What does it mean?”
• Que signifie ce mot ? “What does this word mean?”
• Comment dit-on cela en anglais ? “How do you say that in English?”

Summary

• Qu’est-ce que c’est ? is the standard translation of “What is it?”
• C’est quoi ? is the common informal form.
• Qu’est-ce que c’est que ça ? often shows surprise or disapproval.
• De quoi s’agit-il ? is formal and often means “What is it about?”
• Qu’est-ce que ça veut dire ? means “What does it mean?”
• Qui est-ce ? is used for people, not things.
• Qu’est-ce que c’était ? means “What was it?”