Reply to my question I received on pistonheads:
"Parking Rouge is in a different area to Parking Expo and Parking Rotonde. Parking Rouge is accessed from Avenu du Panorma which runs parallel to the dual carriageway and you access the circuit across a pedestrian bridge. That area is open for practice but I think it might be closed on the Friday but fairly sure I have seen cars in it and I think it might be marshalled so if you are in it you can get out, whether they will let you back in is a different question! However if he has a parking ticket for that area and parks up during practice on Thursday I would be inclined to try and speak to the marshalls then, and just leave the parking ticket visible in the car."
So should not be a problem then
