One of the best ways for automakers to conceal upcoming products during testing on public roads is to use so-called development or test mules that hide a new or modified chassis and drivetrain components under a fake body shell, typically sourced from a model currently in production.
The modified body shell is borrowed from the facelifted Renault Fluence, but it's evident from the photos that the car is sitting on a longer wheelbase and wider platform. It also rides on a taller suspension.
At this point, however, we are not aware if the French brand is working on a new SUV / Crossover or a sedan / station wagon model, but the upcoming Geneva Motor Show in March of 2014 may provide some answers to what's concealed under the sheetmetal.
Photo Credits: CarPix for CarScoopS