French word -eur comes from Middle French -eur (Used to form agent nouns from verbs.)

Detailed word origin of -eur

Dictionary entry	Language	Definition
-eur	Middle French (frm)	Used to form agent nouns from verbs.
-eur	French (fra)	Used to form agent nouns from verbs. Used to form abstract nouns from adjectives; -ness.

Words with the same origin as -eur