This movie reminded me quite a bit of "Ariel," one of Kaurismaki's older films, and I would say that "Ariel" and "The Man Without a Past" are the best of his films that I have seen.
Here, a man is mugged and severely beaten shortly after arriving in Helsinki. He suffers from amnesia and, without any identification, tries to survive as best he can without knowing his own name, let alone his social insurance number. He lives in a cargo container on the Helsinki waterfront, and ends up getting a low paying job with the Salvation Army.
He falls in love with one of the Salvation Army ladies (Kati Outinen, who starred in Kaurismaki's "The Match Factory Girl"), but things get complicated when he eventually learns his real identity. His newfound love seems in jeopardy as he leaves Helsinki for his hometown in order to see a wife who is a stranger to him, and who may or may not be happy to see him again.
I won't spoil the films ending by telling you how things turn out - but I will highly recommend this movie!
I've noticed that some reviewers seem to think that Kaurismaki is making a negative statement about Finland's economy, and I can see why they think so: Most of the Finns you see are living in dingy apartments, cargo containers and dumpsters. But Kaurismaki's films have almost always been about the lower class/lumpen proletariat, in the same way that Eric Rohmer and Whit Stilman make films about the bourgeoisie. In Kaurismaki's "The Leningrad Cowboys Go to America," he portrayed the U.S. in the same fashion, showing mainly rundown neighborhoods and the lower strata of American society.
Finns are known for their melancholy spirit (which some blame for their high suicide rate). It is something that one discerns from the books of Mika Waltari to the songs of Hector, as well as the films of Aki Kaurismaki. We see it in "The Man Without a Past," but I think that the real message of this film is one of hope: Even under the most adverse of living conditions, where one is without material wealth or even memories of the past, one can still find happiness in simple things like a glass of beer and a song on the jukebox, or from bigger things like the love of another.