Le Fil Rouge-inspired sedan spied doing hot laps on world famous track

A car we suspect to be the next-generation Hyundai i40 has been spied testing at (and around) the Nurburgring.

This vehicle, at first glance, looks to be half-size smaller than the US-focused Sonata, and has a sportier overall design.

The prototype's strong shoulder line, wide grille, and swoopy fastback-style rear are seemingly borrowed from the HDC-1 Le Fil Rouge concept, although that car's long bonnet and rear-drive proportions haven't been brought along for the journey.

The yellow sticker on the rear windscreen indicates this prototype is powered by a hybrid drivetrain.

If this is indeed the new i40, it will enter a rapidly shrinking European family sedan market. Once a major part of the continent's motoring landscape, the segment has seen volumes fall sharply as buyers flock to crossovers and small luxury cars.

Other Asian marques have ceased producing competitors – think Nissan Primera, Toyota Avensis and Honda Accord Euro – for this segment, leaving the Germans to battle it out with cars like the Volkswagen Passat, Opel Insignia, and Ford Mondeo.

As with the latest Peugeot 508, the new i40 may be marketed as a "four-door coupe" rather than a straight family sedan. We're speculating here, but the business case for a new i40 would probably only make sense if it's also produced for sale in China.

The current i40, which made its debut back in 2011, is about due for replacement.

We're not certain when this vehicle will make its debut, but given its full body camouflage and the temporary tail-light units, it may not be fully revealed until the latter half of 2019.