According to the Catholic Church, does God punish sinners? When reading the Old Testament it seems that God punishes bad behavior. But according to the Catholic Church (catechism?) are sins punished by God, for example, in purgatory is it more like a karma, that sins themselves cause 'punishments'?
In the RCC, Purgatory is only a place where people eventually destined for heaven go. It is a place of purification and not punishment, before heading into eventual bliss with the all pure God. Unrepentant sinners who do not accept the salvation of Christ are destined for Hell, and will receive punishment for their sins.