"late Middle English humaine, from Old French humain(e), from Latin humanus, from homo ‘man, human being’. The present spelling became usual in the 18th century; compare with humane."
and for man:
"Old English man(n), (plural) menn (noun), mannian (verb), of Germanic origin; related to Dutch man, German Mann, and Sanskrit manu ‘mankind’."
Interestingly enough, Manu was "the progenitor of mankind" and in Persian (which shares roots with Sanscrit) after Islam the equivalent "progenitor" Adam [aa-dam] is also commonly used to intend 'mankind'.