If you live in Brittany or anywhere else in France, you must have received a letter from the NHS explaining the new European Union regulations concerning the European Health Insurance Card (EHIC).
As from 1st May 2010, the United Kingdom is now responsible for the issue of your EHIC instead of the member state where you live (CPAM). You should use your UK EHIC, and not the EHIC issued by the French Health System anymore.
This only applies to people who have registered the E121 or E106 forms issued by the NHS in the UK when they moved to France.
If you haven’t received the application form, along with an explanatory letter, or if you have any queries, you can call the NHS Overseas Healthcare Team on 0191 218 1999 (dialing from France: 0044 191 218 1999) or visit the web site here.
You can also read a previous post about the EHIC here.
To find out how to register with the French health system, see this post here!