En replacing a prepositional phrase beginning with "de"

Hi Mike,

Is it not the case that the noun phrase is "La liberté d'expression" in its entirety?

So "en" is replacing that entire phrase?

https://www.lawlessfrench.com/grammar/en-adverbial-pronoun/

This is how I understand it.

Bonne Journée

Jim

Jim's right. You may get a better understanding if you substitute the full phrase which en replaces:

La liberté d'expression est un droit fondamental mais il faut respecter les limites de la liberté d'expression. --> La liberté d'expression est un droit fondamental mais il faut en respecter les limites.

In English: 

Freedom of expression is a fundamental right but one must respect the limits of the freedom of expression. --> (literally) Freedom of expression is a fundamental right but one must thereof respect the limits.

Now it makes sense.  The lesson is that "en" replaces d+ phrase and La liberte d'expression does not does not begin with "de".  But when you construct the full phrase, it does begin with "de".  Thanks