And as I've already explained, you don't actually understand the sentencing structures/guidelines "here in Europe" properly in any case... quite apart from it being irrelevant to compare apples from one country with oranges from another.
(As just one hint: a murder sentence of "life, with a minimum of 12 years" - which you've misunderstood to be "a 12-year sentence" - does not mean that the person is out on parole after 2/3 of those 12 years. It doesn't even mean that the person is first considered for parole after 2/3 of those 12 years. It means that the person is first considered for parole after 12 years. And even when the person does get parole - which might be after 12 years of imprisonment, or might be after 16 years, or might be after 40 years - their life sentence means that they are closely monitored and evaluated for the remainder of their life on Earth; if the monitoring authorities determine that the person has gone back to posing a risk to the public, the person can be returned to prison, irrespective of whether they actually commit any further offences.)