What kind of car is Professor Zündapp in Pixar's Cars 2?

Professor Zündapp is a Zündapp Janus in Pixar's Cars 2.

Professor Zündapp is an antagonist who works with the film's criminal conspiracy against the World Grand Prix. His design is based on the unusual Zündapp Janus, a small German car produced in the 1950s. The Janus had an exceptionally distinctive layout, with front- and rear-facing seating, and its name refers to the two-faced Roman god Janus.

That design suits Zündapp's role and gives the character a memorable silhouette. Cars 2 uses many real automotive references, but it adapts them into expressive character designs with eyes, mouths, and animated movement.

Zündapp Janus is easy to confuse with other small European cars, particularly the Fiat 500 or Volkswagen Beetle. Those vehicles are not the model represented by Professor Zündapp. The answer names both the manufacturer and the specific model, which is the most precise identification.