Both sides were down to 14 men after 12 minutes for high tackles.
Ntamack had already scored in the fifth minute when lock Grant Gilchrist was red-carded two minutes later for a high tackle on Anthony Jelonch, while recalled France prop Mohamed Haouas saw red for appearing to target scrumhalf Ben White’s head. Such indiscipline could cost Haouas a World Cup place later this year.
Within less than 60 seconds of Gilchrist’s sending off, France had its second try as the tournament newcomer Dumortier was fed by Ntamack in the corner. Ramos scored from nearly the other end of the field after intercepting Russell’s pass and converted his own try.
The Scots didn’t wilt and hit back in the 26th when Jones burst through for a converted score, shortly after powerful winger Duhan van der Merwe had a try in the corner ruled out following a video review.
A Ramos penalty sent France in 22-7 at the break, but Jones rolled over for his second try within 10 minutes of the restart after being set up by fellow midfielder Sione Tuipulotu’s pass inside.
Scotland took maximum points against England and Wales with wins from its opening two matches for the first time in 27 years. But defeat leaves Gregor Townsend five points behind Ireland ahead of their clash.
Scotland, England and France have 10 points.
France 32 (Romain Ntamack, Ethan Dumortier, Thomas Ramos, Gael Fickou tries; Ramos 3 conversions, 2 penalties), Scotland 21 (Huw Jones 2, Finn Russell tries; Russell 3 conversions). HT: 22-7