Unhappily, New Orleans is not the safest of cities after dark. Be careful. Although I wouldn't say it's as dangerous as Rio or Lagos, I'd still caution against wearing too much jewellery, fancy watches, or cutting-edge clothes that scream, 'I have money!!' I'd definitely stay away from sleazy bars. And if you're white-skinned, all-black bars are definitely dangerous. I say this because its a fact, and one that must be accepted. Don't think that just because you have some exotic-sounding accent that that will protect you. Far from it. There have been many instances of foreign tourists' having been mugged -- or worse -- in 'The Big Easy'.
Be careful at night.....Bourbon Street is tons of fun but scary at night so never walk alone. If you are not staying in the French Quarter you have to walk down dark streets to get to the public parking and there are always interesting people lurking in the alleys so watch out.
Walking alone through the French Quarter late at night is a risk. It is a high crime area. They have patrols on motorcycle and horseback through the Quarter, but it is still dangerous.