It's enormous, for a Fumariaceae (if that's what it is).

Here's photos:
Pic: Flowering plant.
Pic: Flowerspike.
It's almost 1 m (4') tall, and was unlabelled in the botanical garden of Gothenburg. These photos were taken in June.

Any of you have a clue? Thanks!

--
Update: It's a Corydalis caseana. Thanks Jimmy!