Most of your recent purchases have been items that were listed on eBay.com and eBay.ca. Neither of these eBay websites allow sellers to charge a surcharge for accepting PayPal.
You did buy a couple of items recently that were listed on eBay.fr (eBay France). I went to the eBay France help pages to see if surcharges were allowed there -- they are not. (See the policy & translation below.)
So no -- your seller is not allowed to charge you extra because you used PayPal to pay. It sounds like you have already paid (good), so I would just politely reply that you will not pay the surcharge because eBay France policy does not allow the seller to charge a surcharge.
If you haven't paid yet, and the seller has added the surcharge to the invoice, you may not be able to pay for the purchase and shipping without paying the surcharge, and you may (or may not) be able to remove the surcharge yourself. I'm not sure what to advise in this case. Sending a message to the seller as above would be a good start.
2. Electronic Payment Services
A seller who accepts electronic payment services such as PayPal, for payment of items purchased on eBay, is not entitled to charge the buyer with additional costs (eg. Additional fee or percentage of the price of sale). In general, the ban is also included in the contractual terms of the company providing the service of electronic money.
2. Services de monnaie électronique
Le vendeur qui accepte les services de monnaie électronique, comme le système PayPal, pour le paiement d'un objet acheté sur eBay, n'est pas autorisé à facturer à l'acheteur des frais additionnels (par ex. frais supplémentaires ou pourcentage du prix de vente). En règle générale, cette interdiction figure également dans les conditions contractuelles de la société fournissant le service de monnaie électronique.
http://pages.ebay.fr/help/policies/listing-surcharges.html
