What the sporting regulations say:
- Parc ferme is an enclosed and secure area in the paddock where the cars are weighed and any other checks deemed necessary by race officials are made.
- Teams must leave their cars here from within three and a half hours of the end of the qualifying on Saturday until five hours before the start of the formation lap on Sunday.
- However, the cars are deemed to be under parc ferme conditions for a much longer period - from the time they first exit the pits during qualifying until the start of the formation lap immediately prior to the race.
- Under these conditions, the work teams may carry out on their cars is limited to strictly-specified routine procedures, which can only be performed under the watchful eye of the FIA Technical Delegate and race scrutineers.
- Fuel may be added to the cars, tyres changed and brakes bled. Minor front wing adjustments are also allowed, but little else. These controls mean that teams cannot make significant alterations to the set-up of a car between qualifying and the race.
- The only exception to this is when there is a "change in climatic conditions", for example a dry qualifying session followed by a wet race, or vice versa. In this case the FIA will give the teams permission to make further appropriate changes to their cars.
- At the end of the race, when the cars have passed the chequered flag, they must be driven straight to the post-race parc ferme without delay or assistance from marshals. The only exception is for the winning driver who may perform an act of celebration before reaching parc ferme, providing he does it safely and without calling into question the legality of his car.