Its much the same as England, except they tend to use mobile speed guns. This may be a motorbike cop with a hairdryer behind a piece of bridgework, or a Gendarme leaning across the roof of his parked blue Renault estate. They've now introduced Renault Méganes and Peugeot 208s that have a large unit on top of the dash and have 360 degree mobile coverage. I usually see a speed trap at some stage, but they are few and far between, but better hidden.
Why rush? Westfields aren't much fun on the motorway, but there are many Roman roads, such as the D338 (N138) which are ideal. There is an automatic 30 limit in all towns and villages. Le Mans is about 5 hours from Calais, and fuel stops can be a problem, as like the UK, most filling stations have closed as the supermarkets have taken over. The small towns are bypassed, and finding the local supermarket isn't easy, but a little research will help.
Houx is quite civilised, Houx annexe is the opposite. Clearly, you don't have much space for luggage. Local supermarkets sell everything. Be prepared for rain and sun. What were you planning for food. Some is available on the circuit.
There are websites for Le Mans enthusiasts, for example Beermountain.com which includes a forum where you can ask embarrassing questions, and ClubArnage who publish a .pdf guide every year.
What else do you want to know?
What else do you want to know