What did Clovis do to the Western Roman Empire after its fall?

The Franks had already been allowed to settle in Holland south of the river Rhine and Belgium by the Romans. They expanded into northern Gaul during the invasions by other Germanic peoples.

Clovis did not do anything the the Western Roman Empire. When he conquered the Domain of Soissons, a Gallo-Roman rump state in central Gaul, the Roman Empire was already dead letter. The Burgundians, Alemanni, Visigoths, Vandals, Sueves and Alans had already taken over most of the lands of the empire.

Clovis'other conquests were at the expense of other Germanic peoples, not the Romans: the Alemanni, and the Visigoths.