If you intend to move to France permanently, it is worth making enquiries with the DSS in Newcastle. For further information, please see the excellent Department of Health website.
For those residing in France for over six months, to obtain medical cover it is necessary to register with the French medical service (known as the Securité Sociale, or more precisely the Caisse Primaire d’Assurance Maladie – primary health insurance fund – for your region). For those over 65 (being the UK retirement age,) no contributions towards the French medical service are required, as there is cover under a reciprocal agreement between England and France.
As recently reported in the English press, the French are now insisting that all those residing but not working in France and who are under the official age of retirement of their country of origin (65 in the UK), may no longer benefit from medical cover provided by the French state. These people must register and pay into the French medical service.