South-Africa is not a very French-car loving country, against what does the 508 compete?
Here we go.
Directly:
-Citroen C5 (which I think it shares the same platform)
-Chrysler Sebring
-Dodge Avenger
-Ford Mondeo
-Honda Accord (Acura TSX in America)
-Hyundai Sonata
-Kia Magentis (Optima in America)
-Mazda 6 (different of the American model)
-Opel/Vauxhall Insignia (Buick Regal in America and China)
-Renault Laguna
-Skoda Superb
-Subaru Legacy
-Toyota Avensis
-Volkswagen Passat
Indirectly:
-Alfa Romeo 159
-Audi A4
-BMW 3-series
-Lexus IS
-Mercedes-Benz C-Class
-Saab 9-5
-Volvo S60