I've heard some whisperings about this... has anything been confirmed? Do we even know which venue he's supposed to be playing and which month it's going to be?

No one knows for sure, but the rumour is he'll play Paris in June. I hope so!

it was on ticketmaster.ie at the announcement of the croke park concert. Something like: "his only other European stops will be Paris and Milan."
I think they deleted it to gain more foreign buyers for Dublin. BTW: Ticketmaster doesn't sell tickets in France and Italy... fortunately

So where are you supposed to buy tickets from?

Don't know yet, as soon as it's announced, you can probably get the links by googling the venues name or by watching here and on housequake

I hope they were right, but I'm almost sure other cities will be announced, it would be very strange if Prince only did one gig at one 'not that obvious' place (Dublin) this summer