An iPad with Wi-Fi and 16 gigabytes of memory costs $200 less in Hong Kong, the former British colony than in Germany and France. Given the risk of having to pay extra duty (and the price of the flight) potential iPad buyers in Frankfurt or Paris should consider a trip to nearby Luxembourg, where Apple's popular device is $35 cheaper.
The sales tax is only one reason for such differences in price. Consumers in Hong Kong also get a better deal because iPads are assembled in mainland China. Buyers in Switzerland have to pay more because there is less competition between retailers. In China and Mexico, the device may be cheaper because people are poorer.
Incidentally, if income is taken into account, consumers in Luxembourg get the best deal: they only have to spend about 0.8% of the city-state's GDP per person on an iPad.