Whilst I completely agree with James - that the micro station is the way to go as far as individual drainage solutions go there are a few errors in his post.
DTU 64.1 states that unless there are extaordinary situations ,such as land which is completely clay or other substratas where infiltration of treated water is not possible ,then one must infiltrate the treated water on your own property.
There are formulas to work out the size of infiltration beds based on water throughput and soil type. Normally the infiltration bed to take treated water from a micro station is much smaller than the traditional epandage system which must have at least 60 metres of pipework .
The list of approved stations is published by the department of health nationally.
There are two distinct types of station and numerous variations within those catagories. Basically ones that can be used for houses in permanent occupation and those for holiday homes. The holiday home ones can be used for permanently occupied houses but not the other way around. The difference is normally that you need a permenant power supply to run the ones for permanent housing whereas if electricity is involved at all for the holiday home variety it will be to power a pump after the micro station and it therefore does not matter if the power goes off and no one is there because if nothing is going in to the system nothing needs to come out !
In most areas of France it will be necessary to have a soil test carried out and an installation design dossier submitted via the Mairie to SPANC ( or their local equivalent ) to get their approval of the proposals before installation begins. They will also need to visit site before the pipework/system is covered up to inspect it and ensure that the installation complies with the regulations and the manufacturers requirements. There is , obviously, a charge for their service.
There are areas of the country where soil tests etc are not required ( notably the Charente ) .
We recommend a number of manufacturers equipment but it all depends on the requirements of each individual site which one we go for.
We are an English Bureau d'Etudes en Assainissement based in Brittany - Armor Environnement , who carry out the site investigations , create the dossiers and submit them to the authorities on the client's behalf.
If we can be of help to anyone in need of new drainage please email us on : firstname.lastname@example.org
Hope this helps