Paris vs City of Light

Paris and City of Light both are nouns.

Word	Noun	Adjective	Verb	Adverb
Paris	Yes	No	No	No
City of Light	Yes	No	No	No

As nouns, Paris and City of Light are synonyms defined as:

Paris and City of Light: the capital and largest city of France; and international center of culture and commerce

Other synonyms of Paris include capital of France, French capital.

Paris (noun)	City of Light (noun)
the capital and largest city of France; and international center of culture and commerce	the capital and largest city of France; and international center of culture and commerce
a town in northeastern Texas
(Greek mythology) the prince of Troy who abducted Helen from her husband Menelaus and provoked the Trojan War
sometimes placed in subfamily Trilliaceae