Unsure whether to post this here, trip reports or scams, but here goes... We had a "local cultural experience" in Paris which we could have skipped. All in all, no harm done, but just wanted to share our experience to help others.
Coming out of the Bastille Metro Station, I was walking ahead of my husband (mistake). He was wearing his day pack in front in the Metro but as we neared the exit he switched to wear it on his back (mistake). We were both tired and jet lagged and not paying enough attention to our surroundings (mistake). I looked back and saw a strange sight out of the corner of my eye. Two young men were walking single file behind my husband, very close to him. There was no one else in the corridor and I thought it was rather odd that they weren't passing him. It took a second for me to register what was really going on. I swung back and saw one of the backpack pockets was unzipped. I yelled at the young man closest to my husband, who gave me "angel eyes" (in the words of one of our French friends). He looked so innocent that I thought I must have made a mistake. However, both young men then quickly passed us and kept looking back at us with worried faces. At some point, they made a u-turn to head back into the subway to find their next victims.
The good news: we had absolutely nothing of value in the backpack. They did steal our shopping bag for buying groceries. We've been to Paris several times, but never in the summer when tourists and pickpockets are in peak season. We got a little too comfortable and learned a valuable lesson at little expense, although I'm sad to think of our nice little grocery bag now leading a life of crime in the Paris subway system.
For the rest of the trip, my husband wore the backpack in front at all times in the Metro and in any very crowded area. I walked with him and we both kept alert. No more problems, although we saw scams galore. My husband is a big, muscular guy. We thought it more likely that I would be a target than him. He had absolutely no idea anyone was behind him and never felt anyone touching or unzipping his backpack. To my fellow travelers - keep your travels wonderful by protecting your valuables!