Goals in either half from Florian David and substitute Ambroise Gboho secured Les Herbiers a David and Goliath match-up against either French champions PSG or their Ligue 1 rivals Caen who meet in the second semi-final on Wednesday.
The National outfit from beside Nantes are emulating the feat of Quevilly, the last third division team to appear in the French Cup final in 2012 when they lost 1-0 to Lyon.
With an operating budget of around two million euros Les Herbiers will have their work cut out against PSG, if Unai Emery's side see off Caen, with the Qatari-backed capital outfit's budget estimated at 540 million euros.
But Les Herbiers can boast the bragging rights in one aspect, having been formed in 1920, half a century before PSG.
With Les Herbiers' ground only built for a crowd of 4,600 Tuesday's semi-final was staged at Nantes' 30,000 plus Stade de la Beaujoire.
The final is on May 8 at the Stade de France.