Because word order in French is generally similar to word order in English, learners of French are only told about the one main case where it clearly differs, namely that adjectives generally follow the noun they modify in French, while in English the rule is just the opposite: adjectives generally precede the noun they modify, unless the expression is one that originated in French, such as:
Note that the plurals of these expressions are notaries public, conditions precedent, attorneys general and courts martial.
To be sure, students learning French study the cases where an adjective can be placed before the noun with a different meaning (there is even a textbook called Un certain style ou un style certain?) and cases where adjectives come before the noun because they express a quality that is inherent in the noun (such as la blanche neige--all snow is white). But in general, it seems to me, they never consider the fact that French syntax can actually differ significantly from English syntax, and to produce an idiomatic translation, the translator will have to rearrange the elements of the sentence.
One example is the title of the book pictured above: Comment parler de musique aux enfants. The title of this book in English (if it were ever translated) would likely be "How to Talk to Children about Music" and not "How to Talk about Music to Children." The book is part of a series on talking to children about various topics, including Comment parler de l'islam aux enfants (literally, "how to talk about Islam to children," but more idiomatically "how to talk to children about Islam"). The most important element, the one being emphasized, comes at the end in English, and the important element is the one that differs from book to book (music, Islam, etc.)
Another reason that syntax may vary between French and English is that apparently English prefers to keep the subject, verb and object (SVO) together and add the other elements to either end of the sentence. Examples of this, taken from the book Initiation au thème anglais by Françoise Grellet, Hachette 2009, include:
Il donne, à Sciences-Po, des cours d’histoire.
He teaches history at Sciences-Po.
ll vit entrer un homme avec, entre les bras, un enfant.
He saw a man come in, with a child in his arms.
Il vendit pour une bouchée de pain ces meubles qu’il aimait.
He sold the furniture he loved for next to nothing.
Syntax also plays a role when translating dialogue from English into French. English speakers use their voice to emphasize the important sentence in the word, while French speakers phrase their thought differently to show emphasis:
J'ai vu un chat noir. I saw a black cat.
C'est moi qui ai vu un chat noir. I saw a black cat.
Mais j'ai bien vu un chat noir. I saw a black cat.
C'est un chat noir que j'ai vu . I saw a black cat.
Finally, the ability to cope with different syntax is also important in legal translation. French codes and statutes are notorious for beginning with lists like this:
Sont punis d'emprisonnement :
Sont passibles d'une amende :
Here the translator will need to add "the following" to keep the SVO nucleus that English requires:
The following crimes are punished with imprisonment:
The following violations are subject to a fine: