when I was in NYC, (this was years ago, but I really can't imagine it being more safe now), I moved in with a native New yorker.
I thought he was really extreme in his practices but he had seen too much in his lifetime there.
I have no idea how paris is so I can't compare.
You must consider where the people are from when they say NYC is safe or dangerous.
I come from another part of the US that is safe.
He advised me:
Do not make eye contact.
He said the bad guys can spot a tourist a mile away, so they will target you.
Try to walk with purpose. Don't look lost.
He would have us separate the money we carry (if we carry any), in case we get mugged.
So if your purse gets taken, perhaps you have some emergency money in your shoe.
He said some will check both your pockets and even other areas. However, He would divide his money in 4 area on his body.
He would shred all trash with ANYTHING that had our personal information on it, even a name. Or he would tear it into small pieces. This seemed silly to me but he would then take it downtown (we lived uptown), and dispose of it there. He said too many people dig through trash looking for information to get to you. He advised it was safer to dispose of it in a neighborhood far away.
He would advise me not to stand near the edge where the subway train comes. He said occasionally someone comes and pushes you off the ledge and apparently the third track will electrocute you.
Don't play the street games of gambling no matter how fun or curious you are. it's a scam.
People will come to you saying they need help, they lost their wallet, etc, that they are a tourist.... it's usually a scam.
It seems harsh but walk away and ignore them.
The apartment buildings are close.
Don't count money or have valuables out even in your home if the windows are open or you have thin curtains.
My roommate, the native new Yorkers would go to the bathroom to count money since it didn't have a window.
The subway:
when I was there it was very crowded during rushhour. So crowded that my face was pretty much pushed in between the shoulder blades of the man in front of me.
People will push you into the other people.
I experienced men on the subway, looking straight ahead as if nothing was amiss, with his genitals completely out and exposed.
I am certain he would do it during rush hour so that people are pushed into him and unwilling against him.
So be aware of your surroundings.
Be aware of glances.
My roommate told me many muggers work together. so they may be on the subway sitting apart in different sections but giving each others signals or texting.
When you get off your stop, they may all get up to follow you.
It never happened to me, but it does happen and once is enough for anyone.
So be aware, and if you see them do that, jump back on the subway before the door closes especially if it has others on.
I was always told to ride in the middle of the train (subway). I heard that is were the operators usually are and more people. If you ride at the end, it's more desolate and more likely you could be raped or mugged, or whatever.
that is for manhattan.
I rode a train once to brooklyn and the middle of the train didn't land near the exit of the station, so that was spooky, but that was really late at night and the whole station was bad.
My friend also advised me if you get into trouble in a residential neighborhood, don't yell for help. People tend to not want to get involved, although I heard the city has changed a bit on this. He said to yell "fire", as with the very tall buildings, people tend to pay attention if there is a possible fire.
I lived in a hispanic neighborhood so his other advice was to yell "Julio" ( a hispanic man's name), as he said hispanic men tend to not want to mess with another man's girl and will back off.
I wouldn't wear nice jewelry, especially earrings. When I was there they had signs everywhere posting about surgeons that fixed torn earlobes because it was common since muggers would rip the earring out of the ear and tear the earlobes.
Don't walk too close to the buildings. There are covered entrances and sometimes men will stand in them. They are concealed a bit since it's dark. They can easily grab a woman walking by and pull her in the building.
Purses... it's better not to carry one. Put them in front of your body and have your eyes on them especially in elevators but really anywhere.
people will stand next to you in an elevator and cut a slit in your purse without you even knowing. I saw it happen to a woman that said she had lived her whole life in new york and never had it happen to her.
Now, I know all that sounds scary but it is better to be aware and follow these things until you see the area you will be staying in and learn more.
Having said all that, I once was walking quickly in the streets on a rainy day with slick shoes.
I completely had my feet pulled out from under me when I slipped and I landed on my back, knocking the air out of me.
soon I see faces hovering over me. They didn't yet realize I couldn't speak because i didn't have my breath.
All I could think of is that I was helpless and would be mugged now. lol
Nothing happened.
Another time I was moving with a very heavy suitcase. i was trying to lug it up the stairs in the train station... apparently I was slowing down the very fast paced people of NYC. Someone grabbed it from me and I was like "hey". Before I could do anything, they just dropped it at the top of the stairs for me.
Odd that they didn't say anything to me like "here, let me help you with that".
I actually think the person was completely annoyed with how I was struggling and did it, not to help as much as they just wanted to get me out of the way.
I will say in addition to the man with the exposed genitals, it was common to see people that were just crazy and would start yelling at a person for sneezing or glancing at them.
I also got harassed alot in neighborhoods by men.
I made the mistake of sitting on the very edge of washington square part in a very lively touristy area, but it was minutes before a man approached me, really crazy eyes and no doubt on drugs.
So even if it looks fine.... be careful.
And as much as I wanted to go to see the ball drop on New Year's Eve, my friend wouldn't let me.
he said there is always trouble and it's full of tourists that just insist on seeing it.
I was in the macy's thanksgiving parade though!
this info is old though.
I was told to stay out of Harlem, but I have heard it has changed and even to live there is extremely expensive.
Harlem was about 128 street and up, I believe.
I'm sure the locals can tell you for certain.