Mexico is an overpopulated, "loud" city, but still one of the safest in the country. Still, a few precautions would be nice.
Such as wallets (it's best to keep the minimum required cash in your pockets, along with a copy of your passport), gold, and jewelry with natural stones are taboo for everyday wear.
It's also not recommended to withdraw money from ATMs at night, or to use green cabs like the Volkswagen Beetle to get around the city - they have a bad reputation despite their low cost.
It's safer to walk along Mexico City's main streets and special tourist routes in the evening. It's worth avoiding visits to the neighborhoods of La Paz, Ciudad Asteca, Istapalapa, Guerrero, and Istapaluca.
