I would laugh if someone said that to me, especially if they intended it as in insult since it just seems so outdated. But it depends on the person I guess.
If you call me a negro, I'm smacking the soul out your body and the crust off your lips so hard your ancestors will feel it.
Meanwhile, you'll be charged with assault, spend time in lockup until bail was posted, and most likely
pay a settlement or medical expenses to the person who called you said word, who gets off scot-free.
we use the term 'negro' in my country because it literally means the black colour in my language. it would be unwise to use the term if I'm in an english speaking country tho cos people could misinterpret and I don't want to happen.