Learn Hardcore French: Mon appartement est petit mais confortable.

(There is a special rule where you use mon before a feminine noun starting with a vowel sound for easier pronunciation, e.g. mon amie, but appartement is genuinely masculine, so mon is required here.)

How do I know that appartement is masculine?

Unfortunately, French gender often has to be memorized word by word.

Some tips:

Most nouns ending in -ment are masculine:
un appartement, un moment, un bâtiment, un gouvernement.
A good habit: when you learn a new noun, always learn it with its article, for example:
un appartement, not just appartement.

Dictionaries always mark gender:

n.m. (nom masculin) = masculine noun
n.f. (nom féminin) = feminine noun

Why are petit and confortable in the masculine singular form?

Adjectives in French must agree with the noun they describe in gender and number.

The noun is appartement → masculine, singular.
So both adjectives must also be masculine singular:
- petit (not petite, petits, or petites)
- confortable (same form for masculine and feminine, but confortables in the plural)

Other possible forms you might see:

Masculine singular: petit, confortable
Feminine singular: petite, confortable
Masculine plural: petits, confortables
Feminine plural: petites, confortables

Why are the adjectives after est instead of before the noun, like in English?

In French, there are two common patterns:

After the verb (as in your sentence)
- Mon appartement est petit mais confortable.
  Here, petit and confortable are predicative adjectives: they come after the verb être and describe the subject.
Directly before or after the noun
- Mon petit appartement confortable. (both before and after the noun)
- Un appartement petit mais confortable. (less common; adjectives usually follow the noun)

Your sentence uses pattern 1:
Subject + être + adjective
This is very common in French and similar to English:
My apartment is small but comfortable.

Could I say Mon petit appartement est confortable instead? Does the meaning change?

Yes, you can say:

Mon petit appartement est confortable.

The basic idea is the same, but there is a slight difference in emphasis:

Mon appartement est petit mais confortable.
→ First you state that it is small, and then contrast that with but comfortable.
Mon petit appartement est confortable.
→ You present small as a regular characteristic of the apartment (almost like part of its identity), then you say that it is comfortable. The contrast is weaker; it sounds more neutral or descriptive.

Both are correct and natural; the first highlights the contrast more clearly.

Why is it mais and not et? What’s the difference?

et means and, simply adding information.
mais means but, introducing a contrast or something unexpected.

Compare:

Mon appartement est petit et confortable.
→ It is small and comfortable (both are just facts, no contrast).
Mon appartement est petit mais confortable.
→ The small size could be seen as a disadvantage,
but surprisingly / fortunately it is still comfortable.

So mais fits better if you want to contrast a possible negative with a positive point.

Could I say C’est petit mais confortable instead of Mon appartement est petit mais confortable?

You can, but the nuance changes:

Mon appartement est petit mais confortable.
→ You clearly identify what you are talking about: my apartment.
C’est petit mais confortable.
→ Literally: It’s small but comfortable.
This is more vague / general. It could refer to the apartment, a room, a place you’re in, etc., depending on context.

In conversation, if it’s already clear you’re talking about your apartment, C’est petit mais confortable is very natural. If you’re introducing the topic, Mon appartement est… is clearer.

Why not il est petit mais confortable instead of repeating mon appartement?

You actually can say:

Mon appartement, il est petit mais confortable.

But in standard written French, you would normally use:

Il est petit mais confortable.
only if the subject (the apartment) is already obvious from context.

So possible patterns:

At the start of a conversation:
Mon appartement est petit mais confortable. ✅ (clear)
Later in the conversation (the subject is known):
Il est petit mais confortable. ✅
(Here il refers to mon appartement.)

How do you pronounce mon appartement? Is there a liaison?

Yes, there is a liaison:

mon appartement is pronounced roughly:
[mɔ̃ napartəmɑ̃]

Details:

mon → [mɔ̃], nasal vowel, the n is not pronounced separately.
Because of liaison, the n sound links to the next word: mon‿appartement → [mɔ̃nap-].
appartement → [apartəmɑ̃] (final -ent is silent; nasal vowel at the end).

So you smoothly link them: mon‿appartement.

How is petit pronounced here? Do you pronounce the final t?

In Mon appartement est petit, petit is pronounced:

[pəti] → the final t is silent in normal speech.

But note:

Before a vowel, there is often liaison:
un petit ami → [œ̃ pətit ami] (you hear the t).

In your sentence, petit is at the end of a phrase before mais, so no liaison, and the t stays silent.

What’s the pronunciation of mais and est? They look like English words.

mais → [mɛ], similar to the English “meh” (short e sound),
not like English “maze”.
est (in il/elle est, mon appartement est) → [ɛ], like a short e sound, similar to “eh”.

So the phrase est petit mais confortable would sound like:
[ɛ pəti mɛ kɔ̃fɔʁtabl] (approx.)

Could I add très or other intensifiers? For example, Mon appartement est très petit?

Yes, French uses adverbs like très (very), assez (quite), plutôt (rather), un peu (a bit) before adjectives:

Examples:

Mon appartement est très petit mais confortable.
→ My apartment is very small but comfortable.
Mon appartement est assez petit mais très confortable.
→ quite small but very comfortable.
Mon appartement est un peu petit mais confortable.
→ a bit small but comfortable.

These adverbs usually go immediately before the adjective they modify.

Is there any difference between appartement and maison?

Yes:

un appartement
→ an apartment / flat, usually part of a larger building.
une maison
→ a (detached / semi-detached) house.

So:

Mon appartement est petit mais confortable.
→ I live in a flat.
Ma maison est petite mais confortable.
→ I live in a house.

Note that maison is feminine, so you would say ma maison, petite (with -e).