There are plenty of occasions in Paris to get scammed, here are a few:

• Pickpockets: They mainly operate in subways and crowded areas like stations, waiting for people to get out of the train or to doze off in the RER B ride from the airport.
• Snatchers: They can snatch your phone, tablet or computer off your hands when the subways is about to leave the station and you are too absorbed reading (or playing Angry Birds) to notice what is going on around you.
• Illusionists: They show you some piece of paper at a restaurant or café, making your phone or wallet or whatever is lying on the table disappear while you explain that you don't understand what they tell you.
• IHP thieves: They might roam around IHP and walk out of the building with the bag or the laptop you left in the conference room (especially at the ground floor). Don't be fooled by the presence of security at the entrance of the building. Locked officed should be fine.