It sounds like it's "the maximum penalty must be at least 1 year", as in "your member state can't enact a law where the maximum penalty is less than 1 year".
At least that's how I read it, but it's confusing.
How would you have read it if it said "with a maximum of one year"?
So it’s a minimum maximum.
This is correct. But the larger point is that even 1 minute of jail time for such "crimes" is unacceptable.