Here are some of the highlights of the industry showcase, which runs until September 24 and is expected to draw hundreds of thousands of car enthusiasts.
If you've always wanted to feel like Lewis Hamilton, the Mercedes-AMG Project One might be for you.
Ahybrid "hypercar" built with Formula 1 technology, it promises 1,000 horsepower and top speeds of over 350 kilometres per hour (218 mph). Mercedes plans to make just 275 units, each costing more than two million euros ($2.4 million).
"It looks like a shark," was one fairgoer's verdict as a crush of people strained to catch a glimpse of the showstopper.
Ten-year-old Moritz was more generous. "You can tell that Mercedes put in a lot of effort," he told AFP, "but I would have preferred bigger spoilers."
Not to be outdone, Bugatti revealed that its own limited edition supercar -- the 2.4-million-euro Chiron -- had just set a heart-stopping new speed record, going from 0 to 400 kmh in 42 seconds.