French comparative constructions introduced by the word comme show a large variety of realizations. However, a thorough observation of their semantics, and of their syntactic properties, leads to conclude that they all fall under a unique analysis: they are adverbial free relative clauses. Indeed, comme phrases show the behavior of manner adverbs (§ 2), the embedded clause is an extraction context (§ 3) and comme has the properties of an adverbial wh- word. Moreover, thanks to the matching effects that constrain the free relative clause construction, we can explain how the comparative semantics proceed – roughly, the fact that two manners are compared (§ 1 and § 5.2).