Cotonou vs metropolis

Cotonou and metropolis both are nouns.

Word	Noun	Adjective	Verb	Adverb
Cotonou	Yes	No	No	No
metropolis	Yes	No	No	No

Cotonou (noun)	metropolis (noun)
chief port of Benin on the Bight of Benin	people living in a large densely populated municipality
	a large and densely populated urban area; may include several independent administrative districts