Hoping that some folks are overstating the level of pickpocketing and intimidation out there (and figuring some are...)
Pickpocketing is a reality. But most of the time, those being robbed just had it coming.
Pickpockets will go for the easy, unsuspecting target. unzipping your backpack in a crowd will be an easy job for many pickpockets. So basic safety rules are to never get anything of value in a place where you would not immediately notice someone reaching into.
Zipped pockets inside of your coat, or a banana bag around your waist (and bag in front of you) might be enough to have the pickpockets choose another easier target.
Also remember that rush hour is happy hour for pickpockets.
And whatever you do, remember that showing off something of value will get you in trouble. Do not, ever, toy around with your new iPhone, even if it's to check the subway map you've downloaded onto the phone. Phones can be grabbed easily by passing thieves, and there is little you'd be able to do about that.
Anyway, I don't intend to scare you, because what I just said were basic "survival" tips valid for any big city around the world.
Actually I used to commute daily on Paris subway, and never have been in any danger or mishap. To tell you the truth, I'll be taking the train from Newark to NY Penn Station in under 2 months and I'm more concerned about safety than I ever was on the Paris transportation.
Last tip, Try not to make eye contact, especially with groups of youths. Some will stare at you, and snap at you if you try to glance back at them.
Ignore people and they will basically ignore you.
Bottomline is that Paris is not more dangerous than any foreign big city. All of those cities around the world become intimidating and have a higher level of danger for the simple fact that, when there, you are a "tourist", and of course, there is no place like home.
But think of the millions of people visiting Paris every year.
Paris is ranked 4th destination in the world for culture and discovery trips.
Paris is ranked 4th destination in europe for lovers, and Marne la Vallée (DLRP) is ranked 1st in europe for family vacations.
That gives you the picture as to the amount of "tourists" in the Paris area. So now, what are the odds for you to get in trouble ?