Verified answer

You're right, it's a bit confusing.

Take an example :

C'est un Français. ln this case Français is a noun.

ll est français. Here français is considered as a predicative adjective.

C'est une bonne actrice. Here actrice is a noun even though bonne is an adjective.

Elle est actrice. Here actrice is a noun in position of a predicate/predicative adjective.

THE SUBSTANTIVE for some words.

So as its name indicates it then we find some words that could be a substantive , sometimes noun and sometime adjective.

So also a verb : un aller-( retour )

A substantive substitutes the noun by the adjective and the adjective by the noun.

Il est avocat .il est un avocat that can be substantive are then correct .According to the role of this substantive

You can perfectly use il/est before a noun actually. It depends more on the context

You use il before an adjective describing a person, and c'est before an adjective describing a situation.

You use il before an adverb and a noun when the noun or adverb are unmodified, nothing has been added to them.

And before the name of somone, you always use c'est.