The race, which starts a week earlier than usual on June 27 to accomodate the Tokyo Olympics, has eight mountain stages and three hilly stages and should suit the 2019 champion Egan Bernal and his Ineos teammate Chris Froome as well as the French duo of Thibaut Pinot and Romain Bardet.
The 3,470km race rarely strays from the mountains even though there are nine flat stages.
"There are 29 climbs, it will be physically challenging throughout," said Tour chief Christian Prudhomme.
"Even the so called flat stages will be very tough for the pure sprinters. There are traps everywhere along the route."
Team Ineos principal Dave Brailsford, the mastermind of seven Tour de France victories, told AFP on the sidelines of the unveiling that he felt undaunted by the route.
"I wouldn't really call it that mountainous, for me it's more hilly and if you look at it the difficulties are spread out over the three weeks," said the 55-year-old Brailsford, who last month revealed he had undergone surgery for prostate cancer.
"We have a brilliant team for this Tour with strength in depth and we can't wait."
Four-time Tour de France champion Chris Froome saw the race differently.
"That is really the hardest route I've seen anywhere in the past five years," he said.
"It will be won and lost in the mountains but that suits me," said Froome, who was limping heavily after breaking his thigh in June.
"I need another month to really say if I can take part anyway."
His teammate Bernal welcomed the course but, like Froome, refused to put himself down as a definite starter, in spite of being the 2019 champion.
"It does look like a good course for me but I can't just come here without talking to the team and deciding which of the riders is best suited to which Tour. I have an open mind."
Another man who disagreed with Brailsford was the Australian sprinter Caleb Ewan, winner of three sprint stages on the 2019 Tour.
"I'm going to have to adapt my training for this. As far as I can see there are only four real sprints, that's the way modern Tours are going," Ewan said.
- Penultimate stage time trial -
The race crosses the sub-Alpine Jura Mountains, the Massif Central, the Vosges, a low range of mountains close to the German border, as well as the tradition giants - the Pyrenees and the Alps.
The Alpe d'Huez, the Galibier and other classic climbs are off the menu in 2020, but the Col de la Madeleine and the Grand Colombier are all on the itinerary.
There is no team time trial but the individual time trial, which ends with a punchy 6km climb up the feared Planche des Belles Filles, could be decisive as it is the final day of actual racing.
The final stage runs from the gritty town of Mantes-La Jolie, 45km north-west of Paris, to the Champs-Elysees on July 19, where the champion will be crowned beneath the Arc de Triomphe.
The final stage and finish is two hours earlier than usual to allow many of the riders to take flights to Tokyo the same evening.
The race starts from the Promenade des Anglais in Nice, scene of a 2016 terror attack which resulted in the deaths of 86 people, with the Cote d'Azur providing some glamour to the opening couple of stages.
Organisers warned, however, that the race gets serious right from the off.
"Anyone who wants to win will have to concentrate right from the start," said race architect Thierry Gouvenou. "Stage two could see someone win by minutes."
Race organisers ASO hope to recapture the spirit of enterprise of the aggressively raced 2019 edition.
"It will be aesthetically sublime," promised Prudhomme, picking out stage 13 for special attention with its alpine summit at Col de la Loze at 2,304 metres making its first appearance in the 107th edition.
The riders will need to climb an old ski-piste maintenance road which has been unearthed and resurfaced.
"It's the prototype for the 21st century mountain we have been looking for," said Prudhomme.
"It has a succession of ruptures and breaks with rapidly changing inclines each one worse than the last one. For the pure climbers, it's a dream come true."
The race features a stage run between the Atlantic islands of Oleron and Re and also pays homage to late former French president Jacques Chirac with a visit to his beloved Correze region in the south-west.
"We are taking full advantage of starting in the south to provide a geographically varied platform to make it as pleasurable as possible," said Prudhomme.