Alpine Academy driver Martins had looked set to take his first victory in F3 at his home race after starting tenth and charging through the field, but was passed by Smolyar in a dramatic tussle on lap 20.
Jenzer Motorsport’s Calan Williams, who started on pole, took his first F3 points finish and his first podium finishing third, while Charouz Racing System’s Logan Sargeant finished fourth.
Trident’s Clement Novalak finished fifth, with newly-announced Sauber Academy driver Juan Manuel Correa (ART Grand Prix) finishing sixth.
Williams had a good start off the line, with Sargeant passing Trident’s David Schumacher to move up to second place by the first turn, while Hitech Grand Prix’s Iwasa moved up into P3.
The virtual safety car was briefly deployed on lap 2 after Johnathan Hoggard, racing in his first weekend for Jenzer Motorsport, went off after a collision and stopped at the side of the track.
By lap 7, Smolyar and Correa were embroiled in a battle for fourth place, while Sargeant took the lead from Williams in a tense three-car battle with Iwasa, who then took second into Le Beausset.
Iwasa took the lead from Sargeant into Signes on lap 10, while further behind the leading pair, Martins passed Correa into fifth using DRS.
Smolyar finally passed Williams into P3 on lap 13, before taking P2 from Sargeant on lap 17.
Iwasa was handed a five second penalty after all four of his wheels left the track while he attempted to pass Sargeant, demoting him from the podium, and leaving him to eventually finish in eighth.
The last few laps saw dramatic place-trading, with Martins, Smolyar, Williams and Sargeant battling for the top three spots.
Martins took the lead on lap 18, but was passed by Smolyar on the final lap.
ART Grand Prix’s Frederik Vesti, who finished 15th, took the bonus points for the fastest lap.
Prema Racing’s Arthur Leclerc, who started in last place, stormed through the pack to finish 12th, putting him on reverse grid pole for this afternoon’s second sprint race.
Hitech Grand Prix’s Jak Crawford will start alongside him on the front row, while Prema’s Olli Caldwell and Dennis Hauger will line up on the second row.
Iwasa will start fifth, with Trident’s Jack Doohan in sixth.