Does the priest ask for reasons to prevent a marriage during a Catholic wedding? In some movies the priest says the following phrase during a wedding: "Whoever is against this marriage should speak now or be silent forever".

Does this tradition exist in the Catholic church (especially in German-speaking parts of Europe)?
I can't speak for the Deutscher Sprachraum directly, but in one of the English books I have there is...


  Therefore if anyone can show any just cause why they may not lawfully be joined together, let him now speak, or else forever hereafter hold his peace.


Yes, that's almost exactly the wording in the Church of England's Book of Common Prayer. It's prescribed for use in the Personal Ordinariates, but that order of service can only be used by Ordinariate priests.

However, in the 1969 rite, this wording does not appear, nor does it appear in the 2016 English translation of the 1991 rite which is currently in use. Consequently I reason that it does not appear in the 1991 normative Latin rite — which I haven't been able to find online — and it would not normally be used in other translations (including German). It did not appear in the 1962 rite.