Lower league Gazelec Ajaccio produced another shock in this year's French Cup as they knocked out high-flying Montpellier.
Meanwhile, Rennes coasted the victory at Valenciennes to reach the semi-finals.
GFCO Ajaccio, who are going from promotion from the third division, scored the only goal of the game against Montpellier through Yohan Bocognano with 15 minutes of the game remaining.
Montpellier, who are currently second in Ligue 1, have now become the second high profile name to crash out of this year's competition after Marseille suffered the same fate to third-tier minnows Quevilly on Tuesday.
L'OM's defeat was the latest set-back for the French giants who, despite qualifying for the quarter-finals of the Champions League with victory over Inter Milan, are struggling in the league.
Rennes secured a comfortable 3-1 victory at Valenciennes in an all Ligue 1 encounter.
The visitors took the lead after 12 minutes through Jonathan Pitroipa, but the home side restored parity thanks to Mamadou Samassa 13 minutes before the break.
But Frederic Antonetti's high flying side soon regained the advantage after 53 minutes with John Boye hitting the target and Youssef Hadji made the game safe for Les Rouges with three minutes remaining.