Squirt something on you and then assist you in wiping it off. Lets them touch you and get empty all your pockets while you concentrate on the sauce. Usually passed off as bird poo or some such. Originated in Rome.

The more common Paris metro trick is the sudden stop. Perp gets in front of you, lets you close and then stops while his mate then runs into you from behind or from opposite direction as you step out from behind the stopped one.