There is only one definition for a Continental European preppy and it is written by somebody who wears Tommy Hilfiger because he thinks Armani, Gucci and Versace are too expensive. He is therefore no European preppy.
The male European preppy will generally start wearing a suit at a younger age than the American one. Armani is probably the best but there are many others too. The brand however must not be visible to the eye in any form of mark or label, which are to be torn or cut off the suit. A tie is generally not worn outside work. More casual wear is mostly bought from your hometown clothes shop run by some childhood friend of yours. You wear local brands rather than international ones. There are also a few decent department stores in the City. For ladies there are much more places to buy clothes from, and accordingly they spend much more time and money shopping than men do. The European preppy of either gender will not be caught dead in a mall. Or wearing Tommy Hilfiger.
The houses in your hometown cost enough to keep the poor out. Your parents have the house in your hometown and the fancy apartment in the expensive part of the City. You go to the university in the City or maybe abroad, a year or two in the States or at Oxbridge will look nice in the CV.
The Continental preppy is fluent in English. To not speak English means you've had a poor education or are a French or German hick. That is not to say that all Frenchmen and Germans are hillbillies. Just 90% of the farmers.
Different countries have different sports like rugby. Tennis and sailing are pretty universal for all European preppies, and in the winter you go skiing to a place that costs enough to keep the poor out. You don't play golf, your dad plays golf. Guys follow some major sports leagues, but hardly ever go to an actual match.
You have good grades in high school to get to the university, where grades don't matter anymore. You just need to graduate, which mostly is a hard job in itself. So if your parents don't pay you trough school and you have to simultaneously study and work to make a living you must be exceptionally talented and hard working to make it. If you have to work you'll also miss a lot of the parties where preppies have a good time and make life-lasting bonds with other preppies.
The European preppy is in deed even more likely to come from Old Money than the American. European preppy families pay high income taxes, but only to a certain limit. Most of the income is not "income", but profit for an offshore company. The middle class pays income tax. Sailing costs enough to keep the poor out. We are the descendants of those who didn't ever have to leave for America.
Italian preppy guy: Damn, that preppy Princess Madeleine of Sweden is super hot.
Norwegian preppy guy: Well, I got to give that one to the Swedes, we don't envy them like our parents did anymore. Oh man, I just saw that guy from Connecticut in a Versace suit with the textile rip-off-tag still in the sleeve!
German preppy girl: Damn Yankees gonna ruin Kitzbuhel. Look, there's that good looking French dude who doesn't speak any English.
French preppy girl: He might be good looking, but he's got no class. He'll miss out on the real after-ski with those few French redneck friends of his. I refuse to talk with him, he just keeps bragging on and on about his parents' vineyard.
Italian preppy guy: Let's go find a good new off-piste hill!