Parc ferme (‘closed park’) is a closed and secured area in the paddock where the cars are weighed and checked by race officials. Cars must be in parc ferme from within three and a half hours of the end of the qualifying until five hours before the start of the race.
Cars are in parc ferme conditions from the time they first exit the pit garage during qualifying until the start of the race. Under these conditions, teams can carry out only limited number of routine procedures under the supervision of the FIA Technical Delegate and race scrutineers.
Teams can add fuel to their cars, as well as minor front wing adjustments, but they cannot make significant setup changes otherwise they must start the race from the pit lane.
Parc ferme was introduced in 2003. – it was the end of using special qualifying engines, brakes and other components which from 2003. couldn’t be replaced after qualifying.
Only exception is when there is a change in climatic conditions – in that case FIA will allow teams to make appropriate changes to their cars.
After the race cars must be driven to the post-race par ferme without delay or assistance. Only exception is when the winning driver perform a celebration, but only if he does it safely and without calling into question the legality of the car.
FIA F1 2017. sporting regulations can be downloaded here.