City of Light vs French capital

City of Light and French capital both are nouns.

Word	Noun	Adjective	Verb	Adverb
City of Light	Yes	No	No	No
French capital	Yes	No	No	No

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

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

Other synonyms of City of Light include capital of France, Paris.

City of Light (noun)	French capital (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