Après la chute, le grimpeur redescend.

Because après is followed directly by a noun phrase.

• après + noun → après la chute
• not après de la chute

So après la chute simply means after the fall.

French uses de after some expressions, but après is not one of them.

Après la chute is an introductory time expression, and the comma helps separate it from the main clause:

• Après la chute, = a time setting
• le grimpeur redescend = the main statement

In French, this comma is very natural when a longer time phrase comes first. You may sometimes see short fronted phrases without a comma, but here the comma is perfectly normal and clear.

In French, singular countable nouns usually need a determiner, such as:

• le / la / les
• un / une
• ce / cette
• mon / ton / son, etc.

So French normally says:

• le grimpeur
• un grimpeur

but not just grimpeur on its own in a normal sentence.

Here le grimpeur means the climber.

Redescend is the present tense of redescendre.

It is the 3rd person singular form:

• je redescends
• tu redescends
• il / elle / on redescend
• nous redescendons
• vous redescendez
• ils / elles redescendent

In this sentence, le grimpeur redescend = the climber goes back down / comes back down / descends again, depending on context.

The prefix re- adds the idea of again, back, or returning.

• descendre = to go down
• redescendre = to go back down / come back down / descend again

So redescend suggests the climber is going downward again or back down, not just moving downward for the first time.

Often, yes, but redescendre is more natural and compact.

Compare:

• Le grimpeur redescend.
• Le grimpeur descend à nouveau.

Both can mean that the climber goes down again, but redescendre is the more direct everyday verb when the idea is back down or down again.

Also, re- can sometimes sound more like a return movement than simply repeating an action.

In redescend, the final -d is pronounced, but there is no -ent here because this is the singular form.

A rough pronunciation is:

• ruh-duh-sahn

More carefully in parts:

• re → often sounds like ruh
• des → sounds like duh here
• cend → sounds like sahn

Important points:

• the final d is heard in redescend
• the vowel in -cend is nasal
• if it were redescendent (plural), the -ent would be silent

Because the sentence is written in the present tense, not the passé composé.

• redescend = present
• est redescendu = has gone back down / went back down

French uses the present for several things, including:

• actions happening now
• general statements
• narration in some contexts

If you wanted to describe a completed past action, you would more likely say:

• Après la chute, le grimpeur est redescendu.

So the original sentence keeps everything in the present style.

No. Redescendre is normally not reflexive here.

• Le grimpeur redescend. = The climber goes back down.

French uses a reflexive verb only when the verb itself requires it or when the meaning is reflexive. Here, the climber is simply performing the action of going down; no reflexive form is needed.

So:

• correct: il redescend
• not here: il se redescend

Not necessarily. It means after the fall, but by itself it does not specify exactly how much time passes.

It could mean:

• immediately after
• sometime later, depending on context

If you wanted to make immediately after clearer, French could use expressions like:

• juste après la chute
• immédiatement après la chute

So the original phrase gives the sequence of events, not the precise delay.

Yes, and the nuance changes slightly.

• Après la chute = after the fall
• Après sa chute = after his/her fall

La chute treats the fall more as an event already known from context. Sa chute links the fall more directly to the climber.

Both are possible, but they do not feel exactly the same.

Because the sentence begins with a noun phrase, not a whole clause.

• Après la chute = after the fall
  
  • here, la chute is a noun
• après qu’il est tombé = after he fell
  
  • here, there is a full clause

So French chooses:

• après + noun
• après que + clause

Since the sentence uses the fall rather than he fell, après la chute is the correct structure.

Yes. English often distinguishes go and come more explicitly than French does.

French redescendre focuses on the downward return movement. Depending on context, English might translate it as:

• goes back down
• comes back down
• descends again

The best English choice depends on viewpoint, but the French verb itself is completely natural.