Generally, this board uses the English language and a lot of our members (as I've discussed this with people here many times before) don't want to translate a single post every time...I'm not attempting to discriminate you in any way, but it would be nice if you could translate what you type into English using something like Google Translate.
Anyways, this is what I got after translating your post:
I want to buy a games console for my cousin. He enjoys playing Xbox360, Wii and PSP. What console I give him? I give it a better console. In addition, I heard it is not easy to find Wii accessories in Paris, yes? Your advice?
I advise that you don't buy him a PSP. The new Playstation Handheld Console--caled "Vita" Is coming out at the end of the year. You can buy him that. The new Wii console, "Wii U", is coming out sometime in next year, so that would also be a little pointless considering the time span of releases. I would definitely get him the Vita or Xbox 360--just ask him which one he wants and make sure the purchase isn't pointless considering the newer consoles are coming out next year (and plus the Wii U is compatible with all Wii games).
Also, please post in the right discussion section next time!