There seems to be only one "precise rule" at Le Mans - they don't have any precise rules
I have it on good authority that the French have two types of rules - ones you have to obey precisely, and those you can ignore. This is done to confuse the British.
We gave up with fires about 20 years ago, as its either too warm or raining. I don't think you'll have problems with a chimnea, provided you're not nicking pallets to burn and cutting them up with a chainsaw
, its not too close to tents, and securitie aren't in a bad mood.