Under the hood, which we'll assume is amidships, there's a 1.6-liter four-cylinder with 256 horsepower sending grunt to the rear wheels, while the front hoops get their power from a 120-hp electric motor 3.7-liter V8 with 600 horsepower, boosted with another 80 hp from an electric motor sending grunt to the rear wheels. In the teaser video there's a slinky bit of carbon fiber action, a healthy dose of the weaved stuff explaining how Peugeot says the Onyx is good for a (conceptual) four liters of fuel per 100 kilometers, which works out to about 58 mpg.
We'll know more when we get to Paris, so for now there are high-res photos above and that teaser vid below.
CORRECTION: The earliest reports about the Onyx suggested a completely different powertrain than Peugeot ultimately debuted. Sorry for any confusion, French supercar fans.