environment vs ambiance

environment and ambiance both are nouns.

Word	Noun	Adjective	Verb	Adverb
environment	Yes	No	No	No
ambiance	Yes	No	No	No

As nouns, ambiance is a hyponym of environment; that is, ambiance is a word with a more specific, narrower meaning than environment:

Other hyponyms of environment include ambience, medium, scene, setting, element, habitat, home ground, melting pot, parts.

environment (noun)	ambiance (noun)
the area in which something exists or lives	the atmosphere of an environment
the totality of surrounding conditions	a particular environment or surrounding influence