Le soir, Marie aime se démaquiller calmement avant de se coucher.

Here Le soir means in the evening / in the evenings, depending on context.

French often uses le + time expression to talk about a habitual time:

• Le matin = in the morning
• L’après-midi = in the afternoon
• Le soir = in the evening

So in this sentence, it sets the scene: In the evening, Marie likes...

It does not necessarily mean one specific evening. It often suggests a general habit.

Because se démaquiller is a reflexive verb, meaning the action is done to oneself.

• démaquiller quelqu’un = to remove someone’s makeup
• se démaquiller = to remove one’s own makeup

So:

• Marie aime se démaquiller = Marie likes removing her own makeup

Without se, the meaning would sound incomplete or would suggest she is removing makeup from someone else.

Se is a reflexive pronoun. It shows that the subject and the object are the same person.

In this sentence:

• Marie ... se démaquiller = Marie removes makeup from herself
• se coucher = to put oneself to bed / to go to bed

So se often corresponds to English ideas like oneself, but in natural English we usually just say:

• to remove your makeup
• to go to bed

French uses reflexive forms much more often than English does.

Because aimer is followed directly by an infinitive when you mean to like doing something.

Pattern:

• aimer + infinitive

Examples:

• J’aime lire. = I like to read.
• Elle aime cuisiner. = She likes to cook.
• Marie aime se démaquiller. = Marie likes to remove her makeup.

So there is no à or de after aime here.

Because after avant, when the same subject does both actions, French uses:

• avant de + infinitive

So:

• avant de se coucher = before going to bed

This is a very common structure:

• avant de partir = before leaving
• avant de manger = before eating
• avant de se coucher = before going to bed

You cannot say avant se coucher.

For the same reason as in se démaquiller: se coucher is also a reflexive verb.

• coucher quelqu’un = to put someone to bed
• se coucher = to go to bed

So avant de se coucher literally means before putting herself to bed, but in natural English we simply say before going to bed.

They are related, but they do not mean the same thing.

• se coucher = to go to bed / to lie down for the night
• dormir = to sleep

So:

• avant de se coucher = before going to bed
• avant de dormir = before sleeping

The first focuses on the moment of getting into bed; the second focuses on the state of sleep.

Because in French, adverbs often come after an infinitive, especially when they describe how the action is done.

So:

• se démaquiller calmement = to remove one’s makeup calmly

This placement is very natural in French.

Compare:

• parler doucement = to speak softly
• marcher lentement = to walk slowly
• se préparer rapidement = to get ready quickly

Sometimes adverbs can move, but se démaquiller calmement is the most natural placement here.

For example:

• Marie aime se démaquiller calmement... = very natural
• Marie aime calmement se démaquiller... = grammatically possible in some contexts, but much less natural here

So for learners, the safest choice is to put calmement after the infinitive phrase.

No.

• Le soir = in the evening / in the evenings, often as a habit or general time
• Ce soir = this evening / tonight, one specific evening

So:

• Le soir, Marie aime se démaquiller... = In the evening(s), Marie likes...
• Ce soir, Marie va se démaquiller... = Tonight, Marie is going to remove her makeup...

Because each infinitive depends on another part of the sentence:

1. aime se démaquiller

   • aime is the conjugated verb
   • se démaquiller is the action Marie likes to do

2. avant de se coucher

   • se coucher is an infinitive after avant de
   • it means before going to bed

So the sentence has one main conjugated verb, aime, and two infinitive verbs that complete the meaning.

Because French does not repeat the subject when using avant de + infinitive if the subject is the same.

So:

• Marie aime se démaquiller calmement avant de se coucher.

This means that Marie is the one doing both actions:

1. removing her makeup
2. going to bed

If the subject changed, French would normally use a different structure, often with avant que:

• Marie se démaquille avant que Paul se couche.

Yes, it is a common verb, especially in everyday contexts.

It is built from:

• maquiller = to put makeup on / to make up
• dé- = a prefix often meaning remove, undo, or reverse

So:

• maquiller = to apply makeup
• démaquiller = to remove makeup

Then the reflexive form:

• se démaquiller = to remove one’s own makeup

A more literal version would be:

In the evening, Marie likes to remove her makeup calmly before going to bed.

That helps show the structure:

• Le soir = in the evening
• Marie aime = Marie likes
• se démaquiller = to remove her makeup
• calmement = calmly
• avant de se coucher = before going to bed

The natural English translation may be a little smoother, but the literal one is useful for understanding the French grammar.