Beat you! I've got a '5'!
So its you destroying the planet. Just find a pre 1960 chassis number plate and you're exempt.
I hear that whilst pre 1960 cars are exempt, everything between then and 1997 is banned from central Paris, and the other towns that adopt the system, so E-Types, XJSs, Ford Mustangs, Cortinas, Escorts and Sierras, Morris Minors, MGBs, TR4s and even Citroen DSs and 2CVs are banned, but not Tiger tanks.