Traffic monitoring service Cnir reported about 310 kilometres of traffic jams at 11.30am and predicted that the situation would get worse before it got better, with saturation point reached during the midday lunch break.
Worst hit, as usual, were the A6 and A7 motorways heading from the south to Paris and the A10 from Bordeaux to Paris.
Although a red alert was issued for Saturday, it was not as bad as the weekend of 8-9 August when holidaymakers travelling in both directions had to deal with 972 kilometres of traffic jams.
In northern France travellers blocked the A1 motorway that joins Lille and Paris overnight near Roye, where a 73-year-old man shot dead three members of the same family and a police officer in an authorised travellers' camp earlier this week.
They burnt tyres, bails of straw and trees, stopping all traffic.They were protesting at a court's refusal to allow the son of one of the victims, who is in jail for selling stolen vehicles, to attend the funeral.
They ended their protest at about 11.30am after another court overruled the decision, also allowing a cousin jailed on the same charges to attend with a police escort in both cases.
Traffic authorities have issued an orange alert for France on Sunday.