street corner vs carrefour

street corner and carrefour both are nouns.

Word	Noun	Adjective	Verb	Adverb
street corner	Yes	No	No	No
carrefour	Yes	No	No	No

As nouns, carrefour is a hypernym of street corner; that is, carrefour is a word with a broader meaning than street corner:

Other hypernyms of street corner include crossing, crossroad, crossway, intersection.

street corner (noun)	carrefour (noun)
the intersection of two streets	a junction where one street or road crosses another