2011? It indeed has one...well, not from the factory, but there are provisions for one. Should be the same part they've used on all the Foci since 2001. I don't believe the HVAC system was reworked all that much for the late model redesign. Easy way to check is to remove the cowling. Passenger side plastic piece at the base of the windshield. Should be at least 3 clips accessible from the engine bay, with some hooks at the back. Not that hard to get off with a little practice. If there is a rectangular opening with a plastic mesh cover on it, then its the same filter that all previous Foci have used. IIRC, they didn't include a filter from the factory as a cost cutting strategy...though the 2010/2011 Foci might have had one.
Now the 2012's are a completely new animal, so I can't comment on them.