The 22-year-old was left clear to take victory after Canary Islander Yeray Lemes, who had an outside chance of the title, hit trouble while in front on Saturday’s final loop of stages.
That followed problems for Tidemand’s other main championship rival, José Suárez, who rolled on Friday.
The result means Tidemand cannot now be caught on the final round, Lemes’s and Suárez’s home event in Spain later this month.
“It wasn’t easy but this was a great rally and I’m delighted to have taken the title with a round still to go,” said a delighted Tidemand. “We’ve had no problems to speak of and my co-driver, Ola, has done a fantastic job too. Victory here makes us both very happy!”
Luxembourg’s Hugo Arellano grabbed an excellent second place on his Junior WRC debut, ahead of Norwegian Marius Aasen in third as nine of the ten competitors – all in Hankook-shod, GEM-fuelled Ford Fiestas R2s – made it to the finish line in Strasbourg.
Lemes briefly clung on to third despite the puncture on SS11 which cost him the lead, but damage to his car meant he was powerless to hold off the charging Aasen on the closing stages.
He limped home fourth while Suárez retired for good on stage 12 when he drove into a tree. It was his second crash of the rally, having rejoined the action after Friday’s roll.
Martin Koci took fifth after a close fight with Michael Burri who completed the top six. Murat Bostanci was just able to hold off Sander Pärn for seventh, while Niko Nieminen was the final finisher in ninth.