By Alan Baldwin
LE CASTELLET, France (Reuters) - Rain washed out most of the final French Grand Prix practice session on Saturday with Valtteri Bottas topping the timesheets for Mercedes.
After fans had spent hours in traffic jams as they tried to reach the circuit on Friday, the grandstands still had many rows of empty seats -- but even if they had been full there was nothing to watch.
Five drivers, including Red Bull's Max Verstappen, did not complete any laps and the times were meaningless with nobody on track for some 40 minutes.
Bottas set his lap of one minute 33.666 seconds before the rain had started.
A few cars ventured out late in the session, including McLaren's Fernando Alonso who won the Le Mans 24 Hours last weekend.
Toro Rosso's Brendon Hartley, one of those who did not set a lap time, had little incentive after being told he will start at the back of the grid after a change of power unit elements.
The New Zealander crashed out on the opening lap of the previous race in Canada and has scored only one point so far this season.
Race stewards said his car had been fitted with a fourth engine and turbo charger, exceeding the 21-race season's allocation of three.
A fourth motor generator unit-heat (MGU-H) had also been fitted along with third replacements of other power unit components.
Sweden's Marcus Ericsson is likely to start from the pitlane after crashing in Friday's first practice with Sauber changing his car's fire-damaged chassis.
Sunday's race will be the first French Grand Prix in a decade and the first at Le Castellet's Paul Ricard circuit since 1990.
Ferrari's Sebastian Vettel leads Mercedes' Lewis Hamilton by a single point after seven races.
(Reporting by Alan Baldwin, editing by Christian Radnedge)