Instead of asking passengers not to take luggage carts up or down escalators, CDG airport simply makes it impossible for users to perform this action. This is an interesting case of a constrained-choice system because it is rare that the system is so overt in communicating its end-goal(s).

(Note also the innovative up escalator/down escalator pictograms, in place of the DOT standard [and easier to understand?] up/down pictograms.)