Alas the perils of being in the EU. As one big market place a company can chose which country it wishes to be based in regardless of were it trades within the EU. One main clincher is taxation. As mentioned Ireland is a favorite as is Luxembourg both because of tax rates.

Ebay and PayPal UK did the same thing a number of years ago which is why your Ebay invoice at the end of the month includes tax/VAT at Luxembourg rates.

None are breaking any laws and many have been doing it for many many years. What can be done, best ask UKIP.

Some will as stated above prefer the UK, taxation in France has shot up since the new government took over and like with our now gone 50% higher rate income tax this will cost their treasury a lot of income that will have to be made up by the poorer of their society that can't get around such things.