As far as i'm aware, the 300 fleet cars have been sold in the UK.
Europe is getting a 2.2l Diesel engine which will put out less than 115g of CO2 (which puts it on the cheapest tax band in Europe) and get 65mpg so great for motorway cruising.
Fleet companies in the UK at least buy huge orders of premium cars and lease them out to other companies. For instance when your company offers you a company car in the UK you're most likely to be offered a BMW 3/5 series, Mercedes C/E class or Audi A4/5. Infiniti has had trouble breaking into this segment (arguably the most profitable and best segment to dominate in Europe) as we've never had a low emissions, high MPG car available until now.
But yes, of course fleet companies do also entail places like Hertz and Enterprise car rental places.