I was pickpocketed in Paris on my very first trip to Europe. I had my 3-year old daughter with me, and was traveling with my mother, who was also targeted. We had flown in to CDG, and were still making our way to the hostel (on the Metro). Luckily, we were prepared, and both wearing money belts, which everything important in them. We lost just a few euros, and learned a great lesson.
*The pickpocket was a very well-dressed man (complete with high-end business suit, tie, and briefcase). He spoke excellent English, and was very, very helpful (directing us to the correct area, helping in other ways).
You cannot tell a pickpocket by appearance! I agree with the other poster who said beware of "overly helpful" people.
*He "just happened" to be heading in the same direction that we were, and boarded the metro train with us. This is where the attempted pickpocketing happened. He chatted with my mother about our trip, and then moved close to me and began chatting.
Be cautious of coincidences! Watch your luggage during friendly chats.
*Immediately after he departed, I saw that the zippers for our suitcases and bags were wide open. This could have been devastating to our trip, if we had not been so careful. Always wear a money belt or other device to keep money, cards, and documents safe.