Cet appartement est plus calme que le premier.

French uses cet instead of ce before a masculine singular noun that starts with a vowel sound or a mute h.

So:

• ce livre = this book
• cet appartement = this apartment
• cet homme = this man

Since appartement begins with a, you say cet appartement.

This is the standard French pattern for a comparison:

plus + adjective + que
= more + adjective + than

So:

• plus calme = calmer / more quiet
• plus calme que le premier = calmer than the first one

French usually does not make a special one-word form like English quieter. It normally uses plus + adjective.

Because French comparatives are usually built with plus, not with an ending like English -er.

Compare:

• English: quiet → quieter
• French: calme → plus calme

So plus calme is the normal way to say quieter.

Because calme agrees with appartement, which is masculine singular. Also, calme is one of those adjectives whose masculine singular and feminine singular forms look the same.

Examples:

• un appartement calme
• une rue calme
• des appartements calmes

You only see a visible change in the plural: calmes.

In French comparisons, que is the word used for than.

Examples:

• plus grand que = taller/bigger than
• moins cher que = cheaper than
• aussi rapide que = as fast as

So plus calme que means quieter than.

Here le premier means the first one or the first apartment.

French often uses:

• article + ordinal when the noun is understood.

So:

• le premier = the first one
• le deuxième = the second one
• la première = the first one (feminine)

In this sentence, le premier refers back to appartement.

Because premier is not standing alone as just an adjective here; it is replacing a noun.

So le premier means:

• the first one
• literally, the first apartment

Without le, the phrase would sound incomplete in this sentence.

Because it refers to appartement, and appartement is masculine.

Ordinal adjectives agree with the noun they describe or replace:

• le premier appartement
• la première maison

Since the missing noun is appartement, the masculine form premier is correct.

Est is the third-person singular form of être, meaning to be.

So:

• Cet appartement est calme. = This apartment is quiet.
• Cet appartement est plus calme... = This apartment is quieter...

Because cet appartement is singular, French uses est.

Yes. French ce / cet / cette / ces can mean this, that, these, or those, depending on context.

If French wants to be more explicit, it can add:

• -ci = this
• -là = that

Examples:

• cet appartement-ci = this apartment
• cet appartement-là = that apartment

So on its own, cet appartement can sometimes be understood as either this apartment or that apartment, depending on the situation.

In plus calme, the final s of plus is often not pronounced, so many speakers say something like plu calme.

A useful thing to remember:

• before a consonant, the s is often silent
• before a vowel sound, you may sometimes hear a z sound through liaison

Because pronunciation of plus varies somewhat by context and speaker, it is a good word to pay attention to when listening to native French.