A striking example is the so-called rule of Vaugelas,which involves the relation between indefinite articles and relative clauses inFrench.

That, on the other hand, is a system all by itself, and it’s rather restricted in its range. It only forms restrictive relative clauses, and then only in a narrow range of syntactic constructions. It can’t follow a preposition (the book of which I spoke rather than *the book of that I spoke) or the demonstrative that (they want that which they can’t have rather than *they want that that they can’t have), and it usually doesn’t occur after coordinating conjunctions. But it doesn’t make the same personhood distinction that who and which do, and it functions as a relative adverb sometimes. In short, the distribution of that is a subset of the distribution of the wh words. They are simply two different ways to make relative clauses, one of which is more constrained.