I actually can't imagine that there are road works planned. Remember, the ACO is the Automobile Club de L'Ouest and they should have some influence on the French road building. On the other hand... ACO... planning... when I start to think of it... there might actually be a bit of truth in it, let's hope not.
As for the Nuerburgring 24Hs being at the same weekend as the LM 24Hs. There's a bank holiday on Thursday before the race and they picked that weekend so that the volunteer helpers won't need to take another day off. That was their line of reasoning, whether it makes any sense or not. Anyway, it's not the first time that the LM 24Hs and the Nuerburgring 24Hs happened at the same weekend. It will be interesting to see what drivers will cover the most miles, on the circuit... and in the air.