Marlies overcame her younger sister Bernadette's leading time from the first run to win her 34th slalom.
The 2011 slalom world champion was third after the first run in the morning. But the elder Schild posted a second run of 53.26 seconds to clinch victory ahead of Frida Hansdotter of Sweden. Bernadette Schild was third overall, and Kathrin Zettel of Austria fourth.
After Hansdotter could not match her time, it was down to Bernadette Schild — nine years younger at 23 and seeking her first win — to stop her sibling equalling the record.
"She wouldn't have got any Christmas presents," Marlies Schild said after winning her third straight race at Courchevel, but her first since winning a slalom race at Soldeu-Grandvalira in Andorra in February 2012.
"It's a very big (weight) falling off my body and my heart. It's nearly two years ago since my last victory. Everyone was asking and asking what the problem was. I wasn't feeling very good for a long time now."
Canada's Marie-Michele Gagnon finished sixth to continue her hot start to the Olympic season.
The 24-year-old from Lac-Etchemin, Que., cemented her reputation as a multi-discipline medal contender for the 2014 Sochi Olympics on a challenging course.
"I'm showing consistency. I'm excited," said Gagnon, who also competes in giant slalom, super-G, super combined and sometimes downhill. "I really feel like I'm in a magical moment right now.
"It was not an easy one today, that's for sure. Especially with not training slalom for a long time, I just wanted to make it down so for sure I'm happy."
Gagnon was fifth in the slalom and 10th in the giant slalom in the opening World Cup, then added a sixth and a 10th-place finish in super-G races earlier this month. She looked poised for her first World Cup podium in giant slalom last weekend before she went out four gates from the finish.
Brittany Phelan, of Mont-Tremblant, Que., was 27th on Tuesday while Elli Terwiel of Sun Peaks, B.C., didn't qualify for the second run. Erin Mielzynski of Collingwood, Ont., and Mikaela Tommy, of Wakefield, Que., were among 25 racers who didn't finish their first runs.
Matching Schneider's record from 1986-95 was an extra bonus for Schild.
"Lindsey (Vonn) was always saying 'If you make records, it's the only thing you remember.' I don't think that's the main thing," Marlies said. "It's just that (it means) you are a good skier when you break records. I'm glad that it's over now."
Last season, she stopped racing in March to recover from another knee injury, but the hunger to keep going fuelled her recovery.
"I lost some years because of injuries and always had the feeling that I could do more, and that's the reason I'm still here," she said. "I had back problems and knee surgery. I didn't know if I could do it again. I was thinking a lot, I was thinking too much. But now I've got my self-confidence back."
World champion Mikaela Shiffrin, who was seventh after the first run, finished 12th.
She won the season's opening slalom at Levi, Finland, last month, but it has been a miserable few days for the 18-year-old.
After failing to finish Sunday's giant slalom in St. Moritz, this was her lowest finish since placing 13th in GS at Maribor, Slovenia, in January, and her lowest slalom finish since 15th in Schladming, Austria, in March 2012.
"I think I needed that today. I can't win everything. I don't think it's good to win everything (because) then I just become complacent," she said. "So I need to know that Marlies is back. That's the coolest thing for me because it's nice to know I'm not the Snow Queen."
She expects fierce competition from Marlies over the next few months.
"For her it wasn't even that impressive. That's saying something. She's an amazing skier and I kept saying that I thought she was the best slalom skier," Shiffrin said. "I don't think I own that title, I think she owns it."
Tessa Worley, the Frenchwoman who won a giant slalom in St. Moritz last weekend, was taken to hospital after falling back on her skis and tearing a right knee ligament in the first run. The International Ski Federation said she will miss the rest of the season, ruling her out of the Sochi Olympics in February.
Bernadette was .13 seconds faster than Hansdotter and .20 clear of her elder sister after the first run.
Marlies, who took slalom bronze at the 2006 Olympics, flew down the Stade Emile Allais course on her second run — .80 seconds faster than Zettel on the first split, .80 quicker on the second, and 1.43 quicker as she crossed the line.
Bernadette was more than one second behind. Still, she earned a big hug from Marlies at the finish line for securing her second career podium result, after finishing second at Lenzerheide, Switzerland, in March.
Being in the unfamiliar position of leading the race gave her some added stress.
"It wasn't too easy to me. I had to breathe deeply to get my heart rate down," Bernadette said. "It's different to stand up there when you're the last one down."
Worley, the giant slalom world champion, toppled backward before twisting forward and landing in the safety netting. She slowly got back up, and was taken to a hospital in Lyon. No further information was immediately available.
"I feel bad for her. She was in really good shape," Marlies said. "I know what it's like to have so many injuries."
Anthony Sechaud, coach of the French women, said the injury likely occurred when Worley got her leg tangled up in the protective netting.
With files from The Canadian Press.