In fact you are registered as a spanish member not even french or english.
The point that you could have misunderstood is that you can log to any ebay website with a single login information.
Coming in France automatic location process made by web browers link you by default to ebay.fr so... it speaks french.
But enforcing in the URL zone of your brrowser to "https://ebay.co.uk" and it will speak english, in the same way enforcing to ebay.es and it will speak spanish. Just add the link to your bookmark.
The sole limitation is that logging to other website than ebay.fr, and you can't see advertisements of french sellers who are not entitled to international operations, so in this specific case you must log to ebay.fr and learn a little pieces of french.
If you want to void some issues in my opinion the good rule to follow is to make the main address (which identify you) match the ebay account type : If your main address is recorded in spain, ebay account regsitration should be spanish, BUT you can add many alternate delivery address (to be not confused with the main address) so you can enter your french address and select it when you buy.
Supposing you still have an home in Spain, you could simply just act as a spanish member as before through ebay.es, just adding a delivery address in France. If you sell some items located in France, when creating the advertisement don't forget to modify the "item location" to France rather than Spain with will pop pup by default.
Limitations if you are a seller :
- using your spanish account on ebay.es, if you do not comply with Ebay International Seller conditions... and your advertisement may not be visible on ebay.fr (or elsewhere)
- Also you can create delivery addresses in paypal account, this need a synchronzation process with ebay book addresses, and this operation is not simple. So the workaround is to create a secondary paypal account with your french address, and to link it to your ebay account. I suppose you have a french bank account with a french Bank Card which will match the main address reccorded in your new paypal account.
