which characters are invalid for usernames?

[avetere]

Well, the title already states it:
I'd like to know, which characters are never allowed inside a username (not ingame, but the account-name) or alternatively: which ones are allowed?

I know there are some invalid ones like # or %, but there are also some legal special characters like Æ ... so ... I'd like to have a list :nod:

[DarkKostas]

Allowed: !()_-=.@[]{} and Alphanumeric
Space is also valid

I dont think i forgot anything else.

[Flame CZE]

And it looks like these are also supported:

éíáýúóå