Darge, who will lead the team alongside Finn Russell, and Gilchrist return in two of three changes to the team unveiled by Townsend on Thursday following Scotland's dramatic 27-26 tournament-opening win over Wales in Cardiff last weekend.
Darge replaces Jamie Ritchie at openside flanker, with the former Scotland captain left out entirely of the matchday 23.
The other two changes to the starting side see Jack Dempsey and Gilchrist return to the pack after back-row Luke Crosbie and lock Richie Gray suffered tournament-ending injuries in Cardiff.
Townsend made it clear Ritchie had been left out purely on selection, rather than fitness, grounds.
"Once we knew Luke was going to be ruled out and Rory was available we had a good look at the back-row and what the best blend would be and we've gone with a Glasgow back-row (of Matt Fagerson, Darge and Dempsey)," Townsend explained.
"The cohesion they have, knowing each other's games and most importantly the blend they have. Rory's an out-and-out seven who can carry the ball well - he's got an all-round game - but we feel the carrying strengths of Matt and Jack give us a better mix this week."
In-form Saracens back-row Andy Christie is on the bench after missing out on the 23 last weekend.
Victory at the Principality Stadium gave Scotland their first success in Cardiff in 22 years.
But the win was only achieved after they nearly squandered a seemingly commanding 27-0 lead, with yellow cards for hooker George Turner and centre Sione Tuipulotu proving a major handicap.
Scotland faced France three times last year, with the Scots having won five of their last seven Murrayfield fixtures with Les Bleus.
They now take on a France side reeling after being hammered 38-17 by titleholders Ireland in Marseille last Friday, with Townsend expecting a strong response from Fabien Galthie's men.
"We've had some cracking games with them in the last 12 months and we'll have to be at our best level physically, in defence and in the contact area, because they have a lot of jackalers in their team," said Townsend.
"They were up against a really good Irish team and they were down a man for the majority of the game.
"From the French perspective, they know they didn't play their best rugby so I would imagine we'll get a reaction from that...We know that with 15 on the field they are a quality team, still a top-three, top-four team in the world."
Scotland (15-1)
Kyle Rowe; Kyle Steyn, Huw Jones, Sione Tuipulotu, Duhan van der Merwe; Finn Russell (co-capt), Ben White; Jack Dempsey, Rory Darge (co-capt), Matt Fagerson; Scott Cummings, Grant Gilchrist; Zander Fagerson, George Turner, Pierre Schoeman
Replacements: Ewan Ashman, Alec Hepburn, Elliot Millar-Mills, Sam Skinner, Andy Christie, George Horne, Ben Healy, Cameron Redpath
Coach: Gregor Townsend (SCO)