Here’s what we know for sure: Lexus will use the Paris Auto Show for the world premiere of a new concept car on September 27. Information and images of the concept will be released in advance, but not until September 17.

With little to go on beyond that, we’re sure it isn’t a derivative of the LF-LC performance hybrid, first revealed at the Detroit Auto Show in January of 2012. The LF-LC is rumored to be heading towards production, with the latest version of the concept scheduled for reveal at the 2012 Australian Motor Show in Sydney.

If Automotive News (subscription required) is correct, the concept may be a Lexus-badged compact crossover, built from the Toyota RAV-4 platform. Such a vehicle (reportedly in the testing stages) would have the BMW X1 and Audi Q3 in its crosshairs, also competing against the revised Acura RDX.

Power is said to come from a turbocharged four-cylinder engine, which should yield decent fuel economy and acceptable performance. For buyers wanting even more fuel frugality, a hybrid variant is also rumored to be in the works.

Compact crossovers are all the rage these days, especially among luxury manufacturers. If Lexus hopes to keep pace against the competition, we say that a model to slot in below the current RX crossover is inevitable.