La facture d’artisan indique le montant retenu.

Because de shortens to d’ before a vowel sound. This is called elision.

So:

• de + artisan → d’artisan

You see this very often in French:

• de école → d’école
• de homme → d’homme

It helps the sentence flow more smoothly in pronunciation.

French normally does not show possession with an apostrophe like English does. Instead, it often uses de.

So English the artisan’s invoice is commonly expressed in French with a de structure:

• la facture de l’artisan = the invoice of the artisan / the artisan’s invoice

In this sentence, la facture d’artisan is a bit more like an artisan invoice or a tradesperson’s invoice, where artisan describes the type or source of the invoice rather than strongly stressing ownership.

This is a very useful distinction.

• la facture d’artisan suggests a more general idea: an artisan’s invoice, an invoice issued by a tradesperson, or an invoice of the artisan/tradesperson type.
• la facture de l’artisan points more clearly to a specific artisan: the artisan’s invoice.

So:

• d’artisan = more generic/category-like
• de l’artisan = more specific/definite

In real life, context decides which one sounds best.

No. Artisan does not usually mean artist.

It usually means:

• craftsman
• craftsperson
• tradesperson
• sometimes skilled manual worker

Examples could include a carpenter, plumber, mason, or other skilled worker.

So in this sentence, artisan refers to someone who does skilled practical work, not a painter or musician.

Because the subject is la facture, which is singular.

Breakdown:

• La facture = the invoice
• indique = indicates

Since la facture is one thing, the verb must be singular:

• la facture indique
• if it were plural: les factures indiquent

So indique agrees with la facture, not with artisan or montant.

The sentence structure is:

• La facture d’artisan = subject
• indique = verb
• le montant retenu = direct object

So the pattern is:

• Subject + Verb + Object

More literally:

• The artisan invoice indicates the retained/selected amount

This is a very normal French sentence order.

French often uses the definite article where English may or may not use the, depending on context.

Here, le montant retenu means the amount retained/selected/agreed on. It refers to a specific amount, not just any amount.

So:

• un montant = an amount
• le montant = the amount

Because the sentence is talking about a particular amount shown on the invoice, le is natural.

Retenu is the past participle of retenir.

Depending on context, retenir can mean things like:

• to retain
• to keep
• to hold back
• to select
• to accept
• to deduct or to withhold in some administrative/financial contexts

So le montant retenu can mean something like:

• the amount retained
• the selected amount
• the accepted amount
• sometimes the amount withheld/deducted, depending on context

The exact English translation depends on the situation, but grammatically it is a past participle used like an adjective.

Because in French, many adjectives—especially past participles used adjectivally—often come after the noun.

So:

• le montant retenu

This is very normal French word order.

You can think of it as similar to:

• la somme due = the amount owed
• les documents signés = the signed documents

French often places this kind of descriptive word after the noun.

Because retenu agrees with montant, and montant is masculine singular.

Agreement here works like this:

• masculine singular: retenu
• feminine singular: retenue
• masculine plural: retenus
• feminine plural: retenues

Since we have:

• le montant → masculine singular

the correct form is:

• le montant retenu

If the noun were feminine, for example la somme, you would get:

• la somme retenue

Not as the main verb of the sentence.

The main verb is:

• indique

Here, retenu is a past participle used like an adjective to describe montant.

So:

• indique = says what the invoice does
• retenu = describes what kind of amount it is

You can paraphrase it as:

• le montant qui est retenu = the amount that is retained/selected

That shows clearly that retenu is describing montant.

A careful pronunciation would be approximately:

• la fak-tyr dar-ti-zan ɛ̃-dik lə mon-tɑ̃ rə-tə-ny

A few helpful points:

• facture sounds roughly like fak-tyr
• d’artisan links smoothly because of the apostrophe
• indique sounds like ɛ̃-dik
• montant has a nasal vowel at the end
• retenu ends with the French u sound, which is not the same as English oo

Also, in normal speech, le may sound quite light.

Yes. That would still be a correct sentence.

• La facture indique le montant retenu = The invoice indicates the retained/selected amount.

Adding d’artisan just gives more information about what kind of invoice it is or where it comes from.

So:

• without d’artisan: more general
• with d’artisan: more specific about the invoice’s source/type