Are you US based? TBH, the stress (my opinion only) of going through customs with something well over your allowance (unless you are a family of 6 or more) is not worth it as the cost savings are not always that great. Having said that, if you come from a state with a high sales tax, it may be worth it as the cost of paying extra customs duty isn't always that painful. It also can take a lot of time, so that is something to keep in mind if your time is limited. The rue de la Paix is spectacular, but you may get better service or quicker service somewhere smaller.
I travel to Europe four times a year and even with nothing to declare, I get antsy.
-e