For shipments coming from a country outside the European Union, the customs service will apply a tax (known as customs duties). 
Amount of the tax = VAT + customs duties + fees. 

Shipments between individuals are exempt from customs duties and VAT, provided that the value of the goods does not exceed €45. 

Goods purchased by mail that are sent directly from a third country (not a member of the European Union) to a consignee in France or in the European Union, with a ex-VAT value of less than €150, are exempt from customs duties. 

Mail order products are taxable from the first Euro (€1). The tax base is calculated as follows: value of goods + shipping costs. 
For more information, visit the French customs website www.douane.gouv.fr