Learn Hardcore French: Le sujet de ce livre est intéressant. - The subject of this book is interesting.

In French, every noun has a grammatical gender, masculine or feminine.
Sujet is a masculine noun, so it takes the masculine singular article le.

le sujet = the subject / topic
(feminine example) la question = the question

You usually have to learn the gender of each noun along with the word itself: un sujet, le sujet (masculine).

What does sujet mean here, and is it the same as English “subject”?

In this sentence, le sujet de ce livre means “the topic/theme of this book.”

Sujet can correspond to English “subject”, but not in every sense:

le sujet d’un livre / d’un film = the topic/theme of a book/film
le sujet d’une phrase = the grammatical subject of a sentence
un sujet d’examen = an exam question/prompt

For a school subject (math, history, etc.), French usually uses une matière (e.g. ma matière préférée, c’est l’histoire), not un sujet.

Why is it de ce livre and not du livre?

Both are possible, but they don’t mean exactly the same thing.

de ce livre = of this book (pointing to a particular book, like “this one here”)
- Le sujet de ce livre est intéressant. → The subject of this book is interesting.
du livre = of the book (more general “the book,” not explicitly “this one”)
- Le sujet du livre est intéressant. → The subject of the book is interesting.

So de ce is de + ce (“of this”), while du is de + le (“of the”).

Could we say sur ce livre instead of de ce livre?

Not in this sentence.

Le sujet de ce livre means “the topic that this book deals with.”
sur ce livre would mean “on/about this book” (something external, talking about the book itself).

For example:

Un article sur ce livre = an article about this book.
Le sujet de ce livre = the topic that the book itself talks about.

So de ce livre is the natural choice here.

Why is it ce livre and not cet livre or cette livre?

Ce / cet / cette / ces are demonstrative adjectives (“this/that/these/those”):

ce before a masculine singular noun starting with a consonant:
- ce livre (this book)
cet before a masculine singular noun starting with a vowel or silent h:
- cet homme, cet arbre, cet hôtel
cette before any feminine singular noun:
- cette maison, cette idée
ces before plural nouns (masculine or feminine):
- ces livres, ces idées

Since livre is masculine and starts with a consonant sound /l/, you must use ce livre.

Why is intéressant at the end, and not before sujet, like “intéressant sujet”?

In this sentence, intéressant is a predicate adjective: it comes after the verb être and describes the subject:

Le sujet … est intéressant. → “The subject … is interesting.”

This structure (noun + être + adjective) always puts the adjective after the verb.

If you put the adjective directly before the noun, you change the structure and often the nuance:

un sujet intéressant = an interesting subject (adjective directly modifying the noun)
Le sujet est intéressant. = the subject is interesting (making a statement about it)

Your sentence uses the second structure.

Does intéressant have to agree with sujet? What happens if it’s feminine or plural?

Yes, adjectives in French must agree in gender and number with the noun they describe.

Base form: intéressant (masculine singular).
Here, sujet is masculine singular, so the form is:

Le sujet est intéressant.

Other forms:

Feminine singular: intéressante
- La question est intéressante.
Masculine plural: intéressants
- Les sujets de ce livre sont intéressants.
Feminine plural: intéressantes
- Les questions sont intéressantes.

How do you pronounce Le sujet de ce livre est intéressant?

Approximate phonetic transcription (standard French):

Le sujet de ce livre est intéressant
→ /lə sy.ʒɛ də sə li.vʁ ɛ ɛ̃.te.ʁe.sɑ̃/

Key points:

le → /lə/ (often sounds like “luh”)
sujet → /sy.ʒɛ/ (final t is silent)
de ce → /də sə/ but the e in de is often dropped in fast speech: /d sə/
livre → /li.vʁ/ (final e is not pronounced; final re = /ʁ/)
est → /ɛ/ (like “eh”; final t is silent)
intéressant → /ɛ̃.te.ʁe.sɑ̃/:
- in- → nasal sound /ɛ̃/
- final -ant is pronounced /ɑ̃/ (nasal vowel, no [t] sound)

You will often hear a liaison between livre and est:
livre est → /li.vʁ‿ɛ/ (small “r” linking to the vowel).

Could we say Ce livre est intéressant instead? Is it the same meaning?

Ce livre est intéressant is correct, but the meaning is slightly different.

Le sujet de ce livre est intéressant.
→ The topic treated in the book is interesting. (Maybe the style is bad, but the idea is good.)
Ce livre est intéressant.
→ The book as a whole is interesting (its topic, style, structure, etc.).

So the original sentence focuses specifically on the subject/topic, not the whole book.

Why not use C’est intéressant here?

You can say C’est intéressant, but it’s less precise.

Le sujet de ce livre est intéressant.
→ Grammatically complete, clear: “The subject of this book is interesting.”
C’est intéressant.
→ “That’s interesting.” It’s more vague; “that” could refer to many things (the book, an idea, a situation, etc.).

You might use C’est intéressant as a follow-up comment:

Le sujet de ce livre est intéressant.
Ah oui, c’est intéressant.

But if you want to name exactly what is interesting, you keep the full sentence with le sujet.

Is intéressant used in French exactly like “interesting” in English?

Often, yes, but French intéressant has some extra uses.

Similar to English:

un film intéressant = an interesting film
une conversation intéressante = an interesting conversation

Extra nuance in French: intéressant can also mean “advantageous / attractive” (especially for prices, offers, deals):

un prix intéressant = a good price, an attractive price
une offre intéressante = an advantageous offer

In your sentence, though, it has the usual meaning: intellectually engaging or worth attention.

Could we say something like Le sujet de ce livre m’intéresse instead? What’s the difference?

Yes, that’s another natural sentence, but it changes the focus.

Le sujet de ce livre est intéressant.
→ General statement: The subject of this book is interesting (in itself).
Le sujet de ce livre m’intéresse.
→ Personal statement: The subject of this book interests me / I’m interested in the subject of this book.

So est intéressant is more objective-sounding, while m’intéresse explicitly shows your interest.