Professor Layton vs. Phoenix Wright: Ace Attorney is coming to European Nintendo 3DS systems on March 28, 2014, Nintendo announced today.
The mash-up launched last November in Japan and so far only as a release window in North America of "early 2014." This is the same release window previously announced for the European version of the game.
The game didn't make an appearance on the North American Nintendo Direct today, despite showing on its European stream. We've reached out to Nintendo for details on the North American release.